It is a little star-dust caught, a segment of the rainbow which I have clutched.
39) have jointed, flexible palps, feelers - often of excessive length - with a short basal segment, and the three terminal segments forming a club, and, in some genera, larvae with legs.
As in the Oligochaeta the peristomial segment is often without setae; but this character is not by any means so constant as in the Oligochaeta.
Apical cell, p. Wall marking limit between the plerome k, initial segment of root-cap. P and the pleriblem Pb.
antennal segment s form a distinct club.
In male beetles, however, the two pairs of genital processes (paramera) belonging to the ninth abdominal segment are always present, though sometimes reduced.
The prostomium overhangs the mouth, and is often of considerable size and, as a rule, quite distinct from the segment following, being A„ f s / 6/ ' A B I.
Turning to the thorax we find that the first segment (prothorax) is distinct and free, with a wide dorsal sclerite.
The female can protrude a long flexible tube in connexion with the eighth segment, carrying the sclerites of the ninth at its extremity, and these sclerites may carry short hairy processes A B D.yrnt,sc/'rle moathd ..
In many of those ants whose third abdominal segment forms a second " node," the basal dorsal region of the fourth segment is traversed by a large number of very fine transverse striations; over these the sharp hinder edge of the third segment can be scraped to and fro, and the result is a stridulating organ which gives rise to a note of very high pitch.
R, Optical section of leptoid (sieve-tube segment) of Phanerogam, with two proteid (companion) cells.
In these ants the difference between the large, heavy, winged males and females, and the small, long-legged, active workers, is so great, that various forms of the same species have been often referred to distinct genera; in Eciton, for example, the female has a single petiolate abdominal segment, the worker two.
It's a one-week tour, each day a separate segment, with everyone riding at their own pace—within reason.
It is, however, always possible to recognize a head, which consists at least of the peristomial segment with a forward projection of the same, the prostomium.
A tissue mother-cell of the xylem may, in the most advanced types of Dicotyledons, give rise to(I) a tracheid; (2) a segment of a vessel; (3) a xylem-fibre; or (4) a vertical file of xylem-parenchyma cells.
A tissue mother-cell of the phloem may give rise to (i) a segment of a sieve-tube with its companion cell or cells; (2) a phloem fibre; (3) a single phloem-parenchyma (cambiform) cell, or a ve~rtical file of short parenchyma cells.
- The Rhynchophora are a group of beetles easily recognized by the elongation of the head into a beak or snout, which carries the feelers at its sides and the jaws at its tip. The third tarsal segment is broad and bi-lobed, and the fourth is so small that the feet seem to be only four-segmented.
Fielde show that an ant follows her own old track by a scent exercised by the tenth segment of the feeler, recognizes other inmates of her nest by a sense of smell resident in the eleventh segment, is guided to the eggs, maggots and pupae, which she has to tend, by sensation through the eighth and ninth segments, and appreciates the general smell of the nest itself by means of organs in the twelfth segment.
In this use the term loses, of course, its morphoI logical value, and it is better to call such a segment of a broken-up I stele a meristele, the whole solenostele with overlapping leaf-gaps being called a dictyostele.
Nephridia generally paired, often very numerous in each segment, in the form of long, much-coiled tubes with intracellular lumen.
The general graphy, principle Arms a and arrangement b, one at eachstation and d B, are connected to the line wire, and are made to rotate simultaneously over metallic segments, 3, 4, and I', 3', 4', at the two stations, so that when the arm a is on segment i at A, then b is on segment I' at B, and so on.
C, Nuclear thread segment ing.
oviducts of Oligochaeta, sperm ducts of Phreoryctes, the coelomoducts occupy, like the nephridia, two segments, the funnel opening into that in front of the segment which carries the external pore.
This consists of a few xylem elements, e a a segment of phloem, pericycle, and usually an arc of h~s endodermis, which closes round the bundle as it detaches ~
- Diagrams of various Earth of several Geoscolicidae, the nephridiopores indicate the segments; to each segment corresponds internally a chamber of the coelom which is separated from adjacent segments by transverse septa,which are only unrecognizable in the genus Aeolosoma and in the head region of other Oligochaeta.
In the latter case each segment of the solenostele frequently resembles a Dktyosteb.
The insects of this order have mandibles adapted for biting, and two pairs of membranous wings are usually present; the first abdominal segment (propodeum) becomes closely associated with the fore-body (thorax), of which it appears to form a part.
The fourth abdominal segment is often very large, and forms the greater part of the hind-body; this segment is markedly constricted at its basal (forward) end, where it is embraced by the small third segment.
The head of an ant carries a pair of elbowed feelers, each consisting of a minute basal and an elongate second segment, forming the stalk or "scape," while from eight to eleven short segments make up the terminal "flagellum."
The more complete replacements, such as the nephridia of the genital segment of Tubifex by a subsequently formed genital duct, may be compared with the succession of the nesonephros to the pronephros in vertebrates, and of the metanephros to the mesonephros in the higher vertebrates..
The funnel, which is not large, appears to open, as a rule at least, into the segment in front of that which bears the external orifice.
On the other hand, in certain Polychaeta the bundles of setae are so extensive that they nearly form a complete circle surrounding the body; and in the Oligochaet genus Perichaeta (=Pheretima), and some allies, there is actually a complete circle of setae in each segment broken only by minute gaps, one dorsal, the other ventral.
When present they are either arranged in four bundles of from one to ten or even more setae, or are disposed in continuous lines completely encircling each segment of the body.
The former view has been extensively held, and it is supported by the fact that in Octochaetus the first segment of the body has a pair of nephridia which is exactly like those which follow, and, like them, persists.
The young insect resembles its parent in most points, but the head is disproportionately large; the anterior abdominal spiracles are on the second segment instead of on the first, and the foot has only a single segment.
In forehand play the bowl as it courses to the jack describes its segment of a circle on the right, in backhand play on the left.
Biisgen that the sweet secretion (honey-dew) of the aphids is not derived, as generally believed, from the paired cornicles on the fifth abdominal segment, but from the intestine, whence it exudes in drops and is swallowed by the ants.
The setae, which are always absent from the peristomial segment, are also sometimes absent from a greater number of the FIG.
The ventral region of the thoracic skeleton is complex, each segment usually possessing a median sternum with paired episterna (in front) and epimera (behind).
It is noteworthy that in this family only among the Polychaeta, the nephridia are not restricted to a single pair in each segment; so that the older view that the gonad ducts are metamorphosed nephridia is not at variance with the anatomical facts which have been just stated.
The genital ducts are limited to one segment (the 8th in Capitella capitata), and there are genital setae on this and the next FIG.
On the other hand, in most Oligochaeta the first segment has in the adult no nephridium, and in the case of Octochaetus the existence of a "head kidney" antedating the subsequently developed nephridia of the first and other segments has neither been seen nor proved to be absent.
- Abdominal Plate (worker of Apis), under side, third segment (magnified twenty times).
notch in tarsal segment for B.
Though the paired arrangement of the nephridia is the prevalent one in the Chaetopoda, there are many examples, among the Oligochaeta, of species and genera in which there are several, even many, nephridia in each segment of the body, which may or may not be connected among themselves, but have in any case separate orifices on to the exterior.
The number of spiracles is greatly reduced; in the adult a pair is present on the mesothorax, sometimes also a pair on the metathorax, and there is always a pair on the first and another pair on the eighth abdominal segment.
From two to four moults occur, after which the " pronymph " stage is reached, which in the insect is moderately active and possesses wing-rudiments reaching to the second abdominal Segment.
to two segments, t.s, Trunk segment.
Frequently reduced in number of pairs; rarely (Capitellidae) more than one pair per segment.
In Lanice conchilega the posterior series of nephridia are connected by a thick longitudinal duct, which seems to be seen in its most reduced form in Owenia, where a duct on each side runs in the epidermis, being in parts a groove, and receives one short tubular nephridium only and occupies only one segment.
(After Montagu.) segment.
In other forms genital ducts and nephridia coexist in the same segment.
The nephridia are sometimes numerous in each segment.
Vascular and 8, 8 and 9, the oviducal pores system always present, upon the 14th and the male pores forming a closed system, upon the 18th segment.
In the genera Pheretima, Megascolex, Dichogaster, &c., each segment contains a large number of nephridia, which, on account of the fact that they are necessarily smaller than the paired nephridia of e.g.
It is disputed whether these micronephridia are or are not connected together in each segment and from segment to segment.
The gonads are, moreover, limited and fixed in numbers, and are practically invariably attached to the intersegmental septa, usually to the front septum of a segment, more rarely to the posterior septum.
The sperm ducts are usually longer than the oviducts; but in Limicolae both series of tubes opening by the funnel into one segment and on to the exterior in the following segment.
12 and 13 are shown the spermathecae of the genera Hyperiodrilus and Heliodrilus, which are simple sacs ending blindly as in other earthworms, but of which there is only one median opening in the thirteenth segment or in the eleventh.
The intestine has a pair of caeca or two or three pairs (but all lie in one segment) in the genus Pheretima and in one species of Rhinodrilus.
In Benhamia caecifera and at least one other earthworm there are numerous caeca, one pair to each segment.
The intersegmental septa are absent save for the division of the first segment.
The vascular system is simple with as a rule direct communication between dorsal and ventral vessels in each segment.
Nerve cord lies in coelom; brain in first segment or prostomium in many forms. Clitellum generally only two or three segments and more anterior in position than in Terricolae.
Nephridia sometimes very numerous in each segment.
There are no setae and apparently only two pairs of nephridia, of which the anterior pair open commonly by a common pore on the third segment after the head, whose segments have not been accurately enumerated.
Nephridia always paired, rarely (Pontobdella) forming a network communicating from segment to segment; lumen of nephridia always intracellular, funnels pervious or impervious.
This corre sponds to the usual pre sence (in the Rhyncho- bdellidae) of three annuli to each segment.
The whole mass lies in the seventh or eighth segment.
The annuli into which segments are externally divided are so deeply incised as to render it impossible to distinguish, as can be readily done in the Oligochaeta as a rule, the limits of an annulus from that of a true segment.
As remarked, the prevalent number of annuli to a segment is three in the Rhynchobdellidae.
In the Gnathobdellidae the prevailing number of annuli to a segment is five; but here again the number is often increased, and Trocheta has no less than eleven.
In Pontobdella and Branchellion the nephridia form a network extending from segment to segment, but there is only one pair of funnels in each segment.
The compound eyes of insects resemble so closely the similar organs in Crustaceans that there can hardly be reasonable doubt of their homology, and the primitively appendicular nature of the eyes in the latter class suggests that in the Hexapoda also they represent the appendages of an anterior (protocerebral) segment.
Behind the antennal (or deutocerebral) segment an "intercalary " or tritocerebral segment has been demonstrated by W.
All of these are to be regarded as primitively post-oral, but in the course of development the mouth moves back to the mandibular segment, so that the first three somitesocular, antennal and intercalary - lie in front of it.
The maxillae of the hinder pair become more or less fused together to form a " lower lip " or labium, and the segment of these appendages is, in some insects, only imperfectly united with the head-capsule.
In some cases, however, it can be shown that the cerci really belong to an eleventh abdominal segment which usually becomes fused with the tenth.
The female genital opening usually lies in front of the eighth abdominal segment, the male duct opens on the ninth.
Animals, 1877), they really belong to the labial segment which has not become completely fused with the headcapsule.
readily movable on the segment (mesothorax) immediately behind - smaller and of less importance where the prothorax is fixed to the mesothorax, as in bees and flies.
Each segment of the thorax carries a pair of legs.
The fifth (distal) tarsal segment carries a median adhesive pad - the pulvillus - on either side of which is a claw.
Enderlein (1901) that these cerci clearly belong to a partially suppressed eleventh segment, and R.
Heymons (1895-1896) has proved by embryological study that in all cases they really belong to this eleventh segment, which in the course of development becomes fused with the tenth.
Smaller appendages (such as the stylets of male cockroaches) may be carried on the ninth segment.
n, First Abdominal Segment.
An ear of another type is found in the swollen second segment of the feeler in many male gnats and midges, the cuticle between this segment and the third forming an annular drum which is connected with numerous nerveendings, while the fine bristles on the more distal segments vibrate in response to the note produced by the humming of the female.
- Hinder Abdominal Segment and Ovipositor of Female Cockroach.
The male opening is on the ninth abdominal segment, to which belong the processes that form the claspers or genital armature.
17), is the mouth or oral piece; the second, explained by the presence of a " latent endoderm-group " in those the antennal segment; the third, the intercalary or prae-mandibular invaginations.
segment; while the fourth, fifth, and sixth are respectively the Embryonic Membranes.
The antennal segment apparently entirely disappears, with the exception of a pair of appendages it bears; these become the antennae; it is possible that the original segment, or some part of it, may even become a portion of the actual antennae.
The intercalary segment has no appendages, nor rudiments thereof, except, according to H.
One of these is the ocular segment, in front of the antennal, and behind the primitive preoral segment.
or " vertex," the compound eyes and the front divisions of the genae are formed by the cephalic lobes of the embryo (belonging membrane analogous to the amnion of higher Vertebrates andto the ocular segment), while the mandibular and maxillary segments known by the same term.
Great difference of opinion exists as to the hypopharynx, which has even been thought to represent a distinct segment, or the pair of appendages of a distinct segment.
The thoracic segments, as seen in an early stage of the ventral plate, display in a well-marked manner the essential elements of the insect segment.
The external part of the lateral field subsequently 14 grows up, and by coalescence with its fellow forms the t6 tergite or dorsal part of the segment.
The cerci, when present, appear in the mature insect to be attached to the tenth segment, but according to Heymons they are really appendages of the eleventh segment, their connexion with the tenth being secondary and the result of considerable changes that take place in the terminal segments.
The stylets, when present, are placed on the ninth segment, and in some Thysanura exist also on the eighth segment; their development takes place later in life than that of the cerci.
In some embryos there is but a single pair of these rudiments (or vestiges) situate on the first abdominal segment, and in some cases they become invaginations of a glandular nature.
The continuous layer of cells from which the nervous system is developed undergoes a segmentation analogous with that we have described as occurring in the ventral plate; there is thus formed a pair of contiguous ganglia for each segment of the body, but there is no ganglion for the telson.
But the protocerebrum contains the ganglia of the ocular segment in addition to those of the procephalic lobes.
- Morphology of an Insect: the embryo of Gryllotalpa, somewhat diagrammatic. The longitudinal segmented band along the middle line represents the early segmentation of the nervous system and the subsequent median field of each sternite; the lateral transverse unshaded bands are the lateral fields of each segment; the shaded areas indicate the more internally placed mesoderm layer.
I, Ocular segment.
The ejaculatory duct which opens on the ninth abdominal sternum in the adult male arises in the tenth abdominal embryonic segment and subsequently moves forward.
This type of active, armoured larva - of ten bearing conspicuous feelers on the head and long jointed cercopods on the tenth abdominal segment - was styled campodeiform by F.
Prominent, unjointed cerci, male with genital armature on second abdominal segment.
First abdominal segment united to metathorax.
A pocrita : Abdomen markedly constricted at second segment.
They differ from other Endopterygota in the multiplication of their Malpighian tubes, and from all other Hexapoda in the union of the first abdominal segment with the thorax.
Further examination also revealed the fact 3 that in certain groups the number of " primaries," or quill-feathers growing from the manus or distal segment of the wing, formed another characteristic easy of observation.
These glands are represented externally by a special plate, the cribellum, which lies in front of the ordinary spinning mamillae, and by a comb of short bristles, the calamistrum, placed in the penultimate segment of the left of the last pair.
Here the eggs are fertilized and here they segment so that the young embryos are formed within their mother's 9 body.
The proboscis is not the only organ of locomotion, being assisted by the succeeding segment of the body, the buccal segment or collar.
In accordance with this manner of feeding, the mouth is kept permanently open and prevented from collapsing by a pair of skeletal cornua belonging to a sustentacular apparatus (the nuchal skeleton), the body of which lies within the narrow neck of the proboscis; the latter is inserted into the collar and surrounded by the anterior free flap of this segment of the body.
The anterior segment broadens and becomes umbrella-shaped; it has a powerful row of cilia round the rim and smaller cilia on the general surface.
The second segment grows downwards like a skirt surrounding the third segment, which is destined to form the stalk.
After a certain time the larva fixes itself by its stalk to some stone or rock, and the skirt-like second segment turns forward over the head and forms the mantle.
The last stage, that in which the folds of the second segment are already reflected over the first, he calls the Typembryo.
Anterior segment, 2.
Second or mantleforming segment.
B, C, D, Stages showing the turning forward of the second or mantle segment.
VII, Usually considered to be the tergum of the genital somite, but suggested by Pocock to be that of the other [According to the system of numbering explained in the text, if VII is the tergum of the praegenital somite (as is probable) it should be labelled Prg without any number, and the somites VIII to XIII should be lettered 1 to 6, indicating that they are the six normal somites of the mesosoma; whilst XV to XVIII should be replaced by the numbers 7 to 12 - an additional suppressed segment (making up the typical six) being reckoned to the metasomatic fusion.] (From Lankester, Q.
In the case of Scorpio this segment is indicated in the embryo by the presence of a pair of rudimentary appendages, carried by a well-marked somite.
The first segment of the mesosoma of Scorpio and Limulus thus remains the first segment, and can be identified as such throughout the Eu-arachnida, carrying as it always does the genital apertures.
- Third leg of Limulus Polyphemus, showing the division of the fourth segment of the leg by a groove S into two, thus giving seven segments to the leg as in scorpion.
cox, Coxa or basal segment of the ex', The exopodite of the sixth leg.
- The 3rd, 4th, 5th and 6th pairs of appendages slender, not evenly tapering, the segments longer than wide; the apical segment short, distally truncate, and provided with a pair of movable claws.
- Comparison of the sixth prosomatic limb of a recent scorpion (B), of Palaeophonus (C), and of Limulus (A), showing their agreement in the number of segments; in the existence of a movable spine, Sp, at the distal border of the fifth segment; in the correspondence of the two claws at the free end of the limb of Scorpio with two spines similarly placed in Limulus; and, lastly, in the correspondence of the three talon-like spines carried on the distal margin of segment six of recent scorpions with the four larger but similarly situated spines on the leg of Limulus; s, groove dividing the ankylosed segments 4 and 5 of the Limulus leg into two.
coxal (maxillary) process, the apical segment tipped with a single movable or immovable claw; appendages of 3rd pair different from the remainder, tactile in function, with at least the apical segment many-jointed and clawless.
Appendages of 2nd pair with their basal segments united in the middle line and incapable of lateral movement; appendages of 3rd pair with only the apical segment many-jointed.
Appendages of 2nd pair folding in a horizontal plane, completely chelate, the claw immovably united to the sixth segment.
Intromittent organ of male in the apical segment of the 2nd prosomatic appendage.
- The plane of the articulation of the appendages of the 1st pair to the prosoma (the retrovert) vertical, the basal segment pro jecting straight forwards at its proximal end, the t raegcn - distal segment or fang closing backwards in a direction subparallel to the long axis of the body.
- The plane of the articulation of the appendages of the 1st pair to the prosoma horizontal, the basal segment projecting ver tically downwards, at least at its proximal end, the distal segment II III IV V VI? ?.I?!1?1UII!119N; / I II III IV V VI 2 3 4 II FIG.
The " retrovert " or bent-back first pair of appendages is provided with a poison gland opening on the fang or terminal segment.
The sperm is removed by the male from the genital aperture into a special receptacle on the terminal segment P FIG.
Appendages of 1st pair consisting of three segments, completely chelate, without poison gland; of 2nd pair slender, leg-like, tipped with three claws, the basal segment without sterno-coxal process taking no share in mastication, and widely separated from its fellow of the opposite side; 3rd, 4th, 5th and 6th appendages similar in form to the 2nd and to each other.
A supplementary pair of tracheae opening behind the basal segment of the 4th appendage of the prosoma.
o, Sterno-coxal process of the basal segment of the second appendage.
d, Fourth segment of 2nd appendage.
Observe that the basal segment of 3 appendage III does not meet its fellow 4 in the middle line.
Respiratory organs tracheal, opening by a pair of stigmata situated immediately behind the basal segments of the 6th pair of appendages on what is probably the sternum of the 2nd opisthosomatic somite and also in some cases upon the 5th segment of the legs.
ramosus is a larger plant, the large white flowers of which have a reddishbrown line in the middle of each segment.
The toga was a piece of woollen cloth in the form of a segment of a circle, 2 the chord of the arc being about three times the height of the wearer, and the height a little less than one-half of this length.
D, a segment of T.
F, detached segment of T.
(From Lankester's Treatise on Zoology, part iv.) segment.
The reproductive organs are usually repeated in each proglottis, and in some families two complete sets of such organs occur in each segment; in a few cases, parts only of the system are duplicated.
The larvae of species belonging to the Culicinae have a prominent breathing tube, or respiratory siphon, on the penultimate (eighth) abdominal segment, and when taking in air hang head downwards (often nearly vertically) from the surface film.
The southern segment of the ancient cone, iswering to the semicircular wall of Somma on the north side, is been almost concealed, but is still traceable among the younger ~cumulations.
The plan pursued was tc build them up gradually in their places by casting segment after segment.
And hence I found the required area of the circular segment 2 x3 A x5 il-A to be x - 5 - 7, &c. And in the same manner might be 3 produced the interpolated areas of other curves; as also the area of the hyperbola and the other alternates in this series (1 - (i+xx) 1, (1 --xx) I, &c....
The reader is also referred to an article by Lord Kelvin (Reprint of Papers on Electrostatics and Magnetism, p. 178), entitled " Determination of the Distribution of Electricity on a Circular Segment of a Plane, or Spherical Conducting Surface under any given Influence," where another equivalent expression is given for the capacity of an ellipsoid.
The body is divided into eleven segments and the protrusible proboscis apparently into two, and the cuticle of the central segment is thickened to form three plates, one dorsal and two ventrolateral.
A pair of pear-shaped, ciliated glands inside lie in the eighth segment and open on the ninth.
The ovaries open in a similar position but never reach farther forward than the fourth segment.
the close union of the foremost abdominal segment (fig.
The true first segment, which undergoes a more or less complete fusion with the thorax is known as the " median segment " or propodeum.
The union of the first abdominal segment with the metathorax has been 8 FIG.
The second (so-called " first ") abdominal segment is often very constricted, forming the " waist " so characteristic of wasps and ants for example.
The constriction of this segment and its very perfect articulation with the propodeum give great mobility to the abdomen, so that the ovipositor or sting can be used with the greatest possible accuracy and effect.
The right sheath C (outer process of the ninth abdominal segment-9) is shown in connexion with the guide B formed by the inner processes of the 9th segment.
These processes are not altogether homologous with those of the ovipositor, being formed by inner and outer lobes of a pair of structures on the ninth abdominal segment.
But the most natural division is obtained by the separation of the saw-flies as a primitive sub-order, characterized by the imperfect union of the first abdominal segment with the thorax, and by the broad base of the abdomen, so that there is no median constriction or " waist," and by the presence of thoracic legs - usually also of abdominal pro-legs - in the larva.
This sub-order, characterized by the " sessile," broad-based abdomen, whose fist segment is imperfectly united with the thorax, and by the usually caterpillar-like larvae with legs, includes the various groups of saw-flies.
The bees which make up this group agree with the Sphecoidea in the short pronotum, but may be distinguished from all other Hymenoptera by the widened first tarsal segment and the plumose hairs on head and body.
Latreille, Familles naturelles du regne animal (Paris, 1825), who recognized the nature of the " median segment."
The typical insectan ovipositor with its three pairs of processes, one pair belonging to the eighth and two pairs to the ninth abdominal segment, can be distinguished in the female.
In the adult there is a pair of such glands opening ventrally on the hindmost thoracic segment, or at the base of the abdomen; but in the young insect the glands are situated dorsally and open to the exterior on a variable number of the abdominal terga.
maxillae, and the foot in the fore and intermediate leg having but a single segment.
The hinder abdominal segments in the male show a curious asymmetrical arrangement, the sixth segment bearing on its upper side a small stalked plate (strigil) of unknown function, furnished with rows of teeth.
The broad head carries, in addition to the prominent compound eyes, three simple eyes (ocelli) on the crown, while the feeler consists of a stout basal segment, followed by five slender segments.
by having a vernier's division fixed to the brass work that holds one segment, so as to slide along a scale on the plate to which the other part of the glass is fitted."
are made with the moving segment displaced alternately on opposite sides of the fixed segment.
One segment is fixed, and the measures are made as in the first method, excepting that the eye-piece is placed symmetrically with respect to the images under measurement.
For this purpose the position angle of the eye-piece micrometer is set to that of the head, and the eye-piece is displaced from the axis of the tube (in the direction of the movable segment) by an amount equal to half the angle under measurement.
The chief objections to the method are that, as one star is in the axis of the telescope and the other displaced from it, the images are not both in focus of the eye-piece,3 and the rays from the two stars do not make the same angle with the optical axis of each segment.
6 This most important improvement would permit any two stars under measurement each to be viewed in the optical axis of each segment.
10 A screen of wire gauze, placed in front of the segment through which the fainter star is viewed, was, employed by Bessel to equalize the brilliancy of the images under observation.
An arrangement, afterwards described, has been fitted in modern heliometers for placing the screen in front of either segment by a handle at the eye-end.
But the method is not available if the separation is to be measured by screws; it is found, in that case, that the direction of the final motion of turning of the screw must always be such as to produce motion of the segment against gravity, otherwise the " loss of time " is apt to be variable.
A small hole is left in the centre of each segment, which is kept open during the fitting to prevent undue pressure upon any one, but is stopped as soon as the circle is completed.
34 Segment of Parabola.
It consists in attaching to the loop or ventral segment of a vibrating body, e.g.
If the length of the thread be k"pt invariable, a certain tension will give but one ventral segment; the fundamental note of the thread is then of the same pitch as the note of the body to which it is attached.
If the plate be small, it is sufficient, in order to bring out the simpler sand-figures, to hold the plate firmly between two fingers of the same hand placed at any point where at least two nodal lines meet, for instance the centre in (1) and (2), and to draw a violin bow downwards across the edge near the middle of a ventral segment.
The surface and solid traced by the revolution of the lesser segment of a circle is termed a "spindle."
If the plane does not contain the centre, the curve of intersection is a "small circle," and the solid cut off is a "segment."
A solution by means of the parabola and hyperbola was given by Dionysodorus of Amisus (c. 1st century B.c), and a similar problem - to construct a segment equal in volume to a given segment, and in surface to another segment - was solved by the Arabian mathematician and astronomer, Al Kuhi.
The greatest shear at C' of the opposite sign to that due to the loading of the longer segment occurs with the shorter segment loaded.
run the shear at C is w X the area of the influence curve under the segment covered by the load, attention being paid to the sign of the area of the curve.
Forward from the head extends a long ramified appendage described as the " frontal shrub," backward from the fourth abdominal segment of the male spreads a fin-like expansion which is unique.
- The body is not encased in a bivalved shell; its articulated segments are at most eleven, those behind the genital segment being without trace of limbs, but the last almost always carrying a furca.
But there is this peculiarity, that the middle segment is sometimes continuous with the broader fore-body, sometimes with the narrower hind-body.
In the latter case the middle segment almost always carries with it to the hind-body a pair of rudimentary limbs, whence the term Podoplea, meaning species that have a pleon with feet.
It may be objected that hereby the term pleon is used in two different senses, first applying to the abdomen alone and then to the abdomen plus the last thoracic segment.
Even this verbal flaw would be obviated if Giesbrecht could prove his tentative hypothesis, that the Gymnoplea may have lost a pre-genital segment of the abdomen, and the Podoplea may have lost the last segment of the thorax.
- First segment of hind-body footless, bearing the orifices of the genital organs (in the male unsymmetrically placed); last foot of the fore-body in the male a copulatory organ; neither, or only one, of the first pair of antennae in the male geniculating; cephalic limbs abundantly articulated and provided with many plumose setae; heart generally present.
- The first segment of the hind-body almost always with rudimentary pair of feet; orifices of the genital organs (symmetrically placed in both sexes) in the following segment; neither the last foot of the fore-body nor the rudimentary feet just mentioned acting as a copulatory organ in the male; both or neither of the first pair of antennae in the male geniculating; cephalic limbs less abundantly articulated and with fewer plumose setae or none, but with hooks and clasping setae.
The terga and pleura of each individual segment overlap those of the segment that serially succeeds it.
A pair of the latter was articulated to the sides of a moderately wide dorsal plate on each segment of the body, and similar limbs were attached to the ventral surface of the head-shield behind the mouth.
These two branches arose from a common basal segment or coxa, the inner surface of which was produced into a strong process underlying the external area.
ABD, is termed a " segment "; if the chord be a diaD meter, the segment is termed a " semi D A circle."
- Data: a, 8, c, c 2, as in (2); height of segment, i.e.
The tenth abdominal segment carries a pair of jointed cerci which are often elongate, and the feelers are always long, while the jaws are usually feeble and membranous, though the typical parts of a mandibulate mouth are present - mandibles, maxillae with inner and outer lobes and palps, and second maxillae (labium) whose lacinae are not fused to form a ligula.
The tenth abdominal segment carries strong, unjointed cerci, while the presence of reproductive armature on the second abdominal segment of the male is a character found in no other order of the Hexapoda.
In animals which exhibit typical segmentation or metamerism, such as segmented worms (Chaetopoda), each segment or metamere possesses its own coelomic cavity, a pair of coelomic ducts, and a pair of nephridia.
The two lateral lobes contain the coelom; each separates off in front a segment which forms the head and presumably then divides again to form anteriorly the trunk, and posteriorly the tail regions.
jaws under Hexapoda); in the presence of a large number of excretory (Malpighian) tubes; in the firm texture of the forewings; in the presence of appendages (cerci) on the tenth abdominal segment; and in the absence of a metamorphosis, the young insect after hatching closely resembling the parent.
The Acridiidae have the feelers and the ovipositor relatively short, and possess only three tarsal segments; their ears are situated on the first abdominal segment and the males stridulate by scraping rows of pegs on the inner aspect of the hind thigh, over the sharp edges of the forewing nervures.
It is held by some morphologists that the mollusc body is unsegmented, and therefore is to be compared to a single segment of a Chaetopod or Arthropod.
Although many fungi have been regarded as devoid of nuclei, and all have not as yet been proved to contain them, the numerous investigations of recent years have revealed them in the cells of all forms thoroughly examined, and we are justified in concluding that the nucleus is as essential to the cell of a fungus as to that of other organisms. The hyphae of many contain numerous, even hundreds of nuclei (Phycomycetes); those of others have several (Aspergillus) in each segment, or only two (Exoascus) or one (Erysiphe) in each cell.
The Y theodolite differs from the transit in that the supports for the telescope are low, that the telescope rests in a cradle the trunnions of which rest on the supports, and that a segment of a circle attached to the cradle replaces FIG.
tr, Trunk segment.
Saccocirrus, which also lives in sand, and more closely resembles the Polychaeta, has throughout the greater length of its body on each segment a pair of small uniramous parapodia bearing a bunch of simple setae.
Polygordius differs from Protodrilus and Saccocirrus in the absence of a distinct suboesophageal muscular pouch, and in the absence of a peculiar closed cavity in the head region, which is especially well developed in Saccocirrus, and probably represents the specialized coelom of the first segment.
- Diagram of a transverse section of Saccocirrus showing on the left side the organs in a genital segment of a male, and on the right side the organs in a genital segment of a female.
In the female there is in every fertile segment a pair of spermathecae opening at the nephridiopores.
In the male there are a right and a left protrusible penis in every genital segment, into which opens the nephridium and a sperm-sac. The wide funnels of the nephridia of this region are possibly of coelomic origin.
Histriodrilus resembles Saccocirrus in the possession of two posterior adhesive processes, and to some extent in the structure of the complex genital organs, which, however, are restricted to a single segment.
It is rather a disputed point whether this dark segment - through which starlight has been seen to passrepresen is a real atmospheric condition or is merely a contrast effect.
In Fucus vesiculosus they arise in lateral pairs; in Ascophyllum they are single and median; in Macrocystis one vesicle arises at the base of each thallus segment; in Sargassum and Halidrys the vesicles arise on special branches.
While, however, in Dictyota the product of the subsequent division in the segment enlarges with each subdivision, the divisions in the cylindrical segment of Sphacelariaceae are such that the whole product after subdivision, however many cells it may consist of, does not exceed in bulk the segment as cut off from the apical cell.
The segment so cut off does not usually divide again by means of a transverse wall, nor indeed by a longitudinal wall which passes through the organic axis of the cell.
In Batrachospermum filaments arise from the carpogonium on all sides; in Chantransia and Scinaia on one side only; in Helminthora the filaments are enclosed in a dense mucilage; in Nemalion, prior to the formation of the filaments, a sterile segment is cut off below.
The Greeks discovered that if a line be divided in extreme and mean proportion, then the whole line and the greater segment are the lengths of the edge of a cube and dodecahedron inscriptible in the same sphere.
showed that, if the large mirror were a segment of a paraboloid of revolution whose focus is F, and the small mirror an ellipsoid of revolution whose foci are F and P respectively, the resulting image will be plane and undistorted.
Again if PQ be any segment of the beam which is free from load, Q lying to the right of P, we find FPFQ, MPMQ=--F.PQ; (12)
If PQ be a short segment containing an isolated load W, we have FeFi.=W, MQ=MP; (3) hence F is discontinuous at a p concentrated load, diminishing by an amount equal to the load as we pass the loaded point to the right, whilst M is continuous.
Apparently there is an influence on the afferent nerves of the part which causes a reflex contraction - some authors say dilatation - of the vessels in the internal organs that are under the control of the same segment of the nervous system as that supplying the area of skin from which the exciting impulse comes.
An ocular segment claimed by the former division is not present or in no case demonstrable in the latter.
In neither does the terminal segment or telson, whether large or obsolescent, whether articulated or coalescent, carry appendages, unless occasionally in fusion with itself.
Between the eyes and the tail-piece in all the orders nineteen segments are counted, the proof of a segment's existence depending on its separateness, complete or partial, or on a sutural indication, or else on the pair of appendages known to belong to it.
They agree with the true crabs in not having appendages (uropods) to the sixth segment of the pleon, the atrophy being complete in the Homolidae and Homolodromiidae, whereas in the Dromiidae and Dynomenidae a pair of small plates appear to be vestiges of these organs.
The last-named species has a straight symmetrical abdomen, with the penultimate segment expanded and strongly calcified to form a back-door to the very unconventional habitation.
Here the articulation of the ocular segment is unusually distinct, and here two characters quite foreign to all the preceding groups come into view.
The genuine Isopoda are divided among the Flabellifera, in which the terminal segment and uropods form a flabellum or swimming fan; the Epicaridea, parasitic on Crustaceans; the Valvifera, in which the uropods fold valve-like over the branchial pleopods; the Asellota, in which the first pair of pleopods of the female are usually transformed into a single opercular plate; the Phreatoicidea, a fresh-water tribe, known as yet only from subterranean waters in New Zealand and an Australian swamp nearly 6000 ft.
Willem it appears that the viscid fluid which causes the adherence of the ventral tube is secreted by a pair of glands in the head whose ducts open into a superficial groove leading from the second maxillae backward to the tube on the first abdominal segment.
The third abdominal segment usually carries a pair of short appendages whose basal segments are fused together; this is the "catch" (fig.
TipX terminal antennal segment with antennal organ.
Potatoes are commonly propagated by planting whole tubers or by dividing the tubers, leaving to each segment or "set" one or two eyes or buds.
r, a rodlet segmented in four, each segment containing one ripe spore.
As a rule only one spore is formed in a cell, and the process usually takes place in a bacillar segment.
The process begins with the formation of brilliant granules (A, B); these increase, and the brilliant substance gradually balls together (C) and forms the spores (D), one in each segment, which soon acquire a membrane and ripen (E).
Each nerve-centre controls its own antimere or segment of the body, receiving sensory impressions from the tentaculocyst and innervating its special subdivision of the muscular system.
Each segment when detached becomes an ephyra, such as that drawn in fig.
The nature of this segment, which is vII.
Very often the basal segment of the protopodite bears, on the outer side, a lamellar appendage (more rarely, two), the epipodite, which may function as a gill.
In this case, the claw-like terminal segment may be simply flexed against the preceding in the same way as the blade of a penknife shuts up against the handle.
4), or, finally, the penultimate segment may be produced into a thumb-like process opposed to the movable terminal segment or finger, forming a perfect chela or forceps, as, for instance, in the large claws of a crab or lobster.
In most cases, however, the palp loses its exopodite and it often disappears altogether, while the coxal segment forms the body of the mandible, with a masticatory edge variously armed with teeth and spines.
The podobranchiae are clearly epipodites, or, more correctly, parts of the epipodites, and it is probable that the arthroand pleuro-branchiae are also epipodial in origin and have migrated from the proximal segment of the limbs on to the adjacent body-wall.
In the majority of the Decapoda there is a saccular invagination of the integument in the basal segment of the antennular peduncle having on its inner surface " auditory " setae of the type just described.
8 the weight on the platform is transferred by levers to the vertical steel band, A, which is wrapped round an arbor on the axle of the disk - wheel, B, to which is rigidly attached the toothed segment, C. The weight, D, is rigidly attached to the axle of the wheel, B, and the counterbalance, E, is hung from the wheel, B, by means of a cord wrapped round it.
The toothed segment, C, actuates the pinion, F, which carries the finger, G, and this finger remains fixed in position so long as the person is standing on the platform.
If now a small weight, as a penny, be passed through the slot, H, it falls into the small box, I, and causes the lever, J, to turn; the lever, J, which turns in friction wheels at K, and is counterbalanced at 0, carries a toothed segment, L, which actuates a small pinion on the same axle as F, and is free to turn on that axle by a sleeve.
From each segment, near its base, a stalked peltate sporangiophore arose; this bore four sporangia, which hung parallel to the stalk.
The older view was that it was a fertile segment of the leaf; and though its ventral position presents a difficulty, this must be regarded as a possible explanation; the occasional occurrence of sporangia on the lamina in Botrychium has been regarded as supporting it.
Probably the chaetae preceded the development of parapodia, and by their concentration and that of the muscular bundles connected with them at the sides of each segment, led directly to the evolution of the parapodia.
as pairs in each ring-like segment or somite of the body, and some of these are in all cases retained as gonoducts and often as renal excretory organs (green glands, coxal glands of Arachnida, not crural glands, which are epidermal in origin); but true nephridia, genetically identical with the nephridia of earthworms, do not occur (on the subject of coelom, coelomoducts and nephridia, see the introductory chapter of part ii.
This segment is indicated embryologically by its paired coelomic cavities.
Very probably the power which the appendage of a given segment has of assuming the perfected form and proportions previously attained by the appendage of another segment must be classed as an instance of " homoeosis," not only where such a change is obviously due to abnormal development or injury, but also where it constitutes a difference permanently established between allied orders or smaller groups, or between the two sexes.
(6) Two rami developed (usually, but perhaps not always, the equivalents of the endopodite and exopodite) supported on the somewhat elongated corm (basal segment).
(7) The endopoditic ramus is greatly enlarged and flattened, without or with only one jointing, the corm (basal segment) is evanescent; often the plate-like endopodites of a pair of such appendages unite in the middle line with one another or by the intermediary of a sternal up-growth and form a single broad plate.
Only one somite following the first post-oral or mandibular segment has its appendages modified as jaws.
Papuan weapons are the bow and arrow (in the Fly River region, the north and north-east coasts); a beheading knife of a sharp segment of bamboo; a shafted stone club - rayed, disk shaped or ball-headed (in use all over the island); spears of various forms, pointed and barbed; the spear-thrower (on the Finsch coast); and hardwood clubs and shields, widely differing in pattern and ornamentation with the district of their manufacture.
Each segment is again divided by lateral fissures, which do not extend quite to the posterior border of the organ; of the central lobes thus cut off, the right is rather the larger, and has two fissures in its free border dividing it into lobules.
The salivary glands are the modified nephridia of the segment of the oral papillae.
The Annelidan features are: (I) the paired nephridia in every segment of the body behind the first two (Saenger, Balfour); (2) the presence of cilia in the generative tracts (Gaffron).
Then the square of the ordinate intercepted between the diameter and the curve is equal to the rectangle contained by the portion of the diameter between the first vertex and the foot of the ordinate, and the segment of the ordinate intercepted between the diameter and the line joining the extremity of the latus rectum to the second vertex.
The conics are distinguished by the ratio between the latus rectum (which was originally called the latus erectum, and now often referred to as the parameter) and the segment of the ordinate intercepted between the diameter and the line joining the second vertex with the extremity of the latus rectum.
Also he gives two different reckonings of the segmentation, counting first eleven body segments without the caudal furca (p. 40), and then the caudal furca as itself the eleventh segment (p. 41).
Radius confluent with ulna, and tibia with fibula; tarsus (astragalus and calcaneum) elongate, forming an additional segment in the hind limb.
There are usually nine tarsal elements in the Caudata; this number is reduced in the Ecaudata, in which the two bones of the proximal row (sometimes coalesced) are much elongated and form an additional segment to the greatly lengthened hind-limb, a sort of crus secundarium.
It's a one-week tour, each day a separate segment, with everyone riding at their own paceâ€”within reason.
Bathymetry and sidescan sonar imagery together reveal a slow-spreading ridge segment that has a large composite volcanic plateau at its center.
abnormalityefects in the lens underlie complex anterior segment abnormalities of the Pax6 heterozygous eye.
black and white years the black-and-white segment there are also.
Each segment has four tiny bristles (tough hairs) underneath its body.
However, a system that uses segment concatenation does not necessarily need such a synthesizer.
Systems with segment concatenation use small speech segments taken from human speech to create synthetic speech.
contiguous segment - over a third.
This work introduces a novel approach to decoding for segment models in the form of a stack decoder with A * search.
A large kitchen, long disused linked to a strangely cool room used a s a pantry occupied one segment of the level.
The use of a loading dose of clopidogrel in non-ST segment elevation ACS patients prior to angiography prolongs their bleeding time.
An electric segment follows before a two song encore.
factual recall within a segment of your syllabus?
Crystal structure of a heparin and integrin binding segment of human fibronectin.
The segment that drains glomerular filtrate from the Bowman's capsule is the proximal convoluted tubule.
ING also said that its insurance segment would fund up to EUR 277 million in equity finance toward the deal.
This prevents duplicating a value when a neighboring segment sets a formant on the boundary.
learning the fundamentals non-standard segment where all states except policy limits the.
Treatment requires a short segment bypass graft to remove the risk of rupture.
In terms of visual daring there's nothing else in the family hatchback segment to match the Civic's radical styling.
Figure 3. Lack of effect of morphine on the responses of the longitudinal smooth muscle of a segment of guinea pig ileum in vitro.
The effect on the miss, false alarm and segment impurity rates is given in Table 5.
The segment with the steam inlet can be seen in place already.
Other posterior segment complications included macular edema (four) and epiretinal membrane involving the macula (two ).
A special segment examines the properties of atoms, explaining how atomic mass and atomic numbers are calculated.
The opening segment has a very space rock feel to it, full of swirling synth effects creating a very meditative mood.
mournful tune with violin adding an intense atmosphere to the song's opening segment.
normal curve Segment 179) codes appeared in a segment: Graphic Distribution of frequencies shows a perfect normal distribution curve.
oscillation angle for all frames in each segment.
Side of the pelvic osteotomy was 2cm shorter in the femoral segment.
peel the prawns, leaving the last tail segment in place.
pen plotters, a segment can only be modified by redrawing the whole picture.
Delayed spontaneous bladder perforation - no particular intestinal segment is more predisposed.
perianth segment is covered with tiny, short, curved hairs.
The platoon headquarters can provide the mobile patrols along the platoon headquarters can provide the mobile patrols along the platoon segment of the route.
A chest X ray showed an apical pneumothorax on the left side with inferior displacement of the distal fracture segment.
The output primitives are sent to the active workstation and stored in the segment.
quadrature of the parabola Archimedes finds the area of a segment of a parabola cut off by any chord.
ribosome entry segment leads to enhanced binding of a group of protein factors.
Large runabout segment (20 to 29 feet) Cobalt ranks highest in the large runabout segment (20 to 29 feet) Cobalt ranks highest in the large runabout segment for a fifth consecutive time.
The television show ' Inside edition ' ran a segment showing various ruses to lure women out of malls.
segment of ileum is used.
segment of the electorate.
segment of similarity between two sequences, use BestFit.
segment of the market in the short term.
The guests at the single solution events are highly segmented group of people in a growing consumer segment.
The real-time image allows you to view the retina and anterior segment with ease using the 20 second video capture feature.
LS: We realized that carp fishing is the fastest-growing segment in the European market today.
Learning the fundamentals non-standard segment where all states except policy limits the.
In both instances the residues of the protein kinases that are dephosphorylated are situated within the activation segment of the kinase.
selector specified in BX is not a code segment or is invalid.
As a note of warning there are some minor spoilers so feel free to skip this segment of the review.
stent grafting of the femoral segment is a straightforward procedure in selected patients.
These interactions appear to play a crucial role in ordering the activation segment that in turn provides the peptide substrate recognition site.
tarsal segment on each front leg.
threonine residue which lies within the activation segment, a modification essential for generating kinase activity.
threonine in the activation segment whose phosphorylation is essential for activity.
Sudden mesenteric vein thrombosis leads to edema and hemorrhage in the affected intestinal segment.
Road Segment and Area avoidance Would you like to avoid traffic tie-ups or roadwork?
Average HR splits will give an accurate average per lap / segment / equipment etc. 100-hour, 3-mode countdown timer.
The segment of tourism undergoing the fastest growth is nature-based tourism, which includes ecotourism (WTTC, 2000 ).
The higher the value, the further from edge-on, the view has to be for the surface segment to appear transparent.
Both any initialised const B and global var C will be stored in the Data Segment, which is limited to 64K bytes.
The solution is to deploy the anonymous access wap on a perimeter network segment that does not have access to the corporate network.
While it is not improbable that the collar-pores and the proboscispores may evacuate excretory substances, there can be little doubt that their primary function is to regulate the turgidity of the segment to which they respectively belong.
This remark applies to the finding of the area of a parabolic segment (mechanical solution) and of a spiral, the surface and volume of a sphere and of a segment thereof, and the volume of any segments of the solids of revolution of the second degree.
The first book contains forty-four propositions, and those in which the most important results are finally obtained are: 13 (surface of right cylinder), 14, 15 (surface of right cone), 33 (surface of sphere), 34 (volume of sphere and its relation to that of circumscribing cylinder), 42, 43 (surface of segment of sphere), 44 (volume of sector of sphere).
3, 4), and of constructing a segment of a sphere similar to one given segment and having (a) its volume, (b) its surface, equal to that of another (5, 6).
(3) On Conoids and Spheroids (Peri konoeideon kai sphairoeideon) is a treatise in thirty-two propositions, on the solids generated by the revolution of the conic sections about their axes, the main results being the comparisons of the volume of any segment cut off by a plane with that of a cone having the same base and axis (Props.
The second book in ten propositions is devoted to the finding the centres of gravity (I) of a parabolic segment, (2) of the area included between any two parallel chords and the portions of the curve intercepted by them.
(6) The Quadrature of the Parabola (Tetragonismos paraboles) is a book in twenty-four propositions, containing two demonstrations that the area of any segment of a parabola is a of the triangle which has the same base as the segment and equal height.
(7) On Floating Bodies (Peri okoumenon) is a treatise in two books, the first of which establishes the general principles of hydrostatics, and the second discusses with the greatest completeness the positions of rest and stability of a right segment of a paraboloid of revolution floating in a fluid.
But the legs carry peculiar spines, and the terminal tarsal segment is cup-shaped at the end; from this hollow a delicate bladder (fig.
I, 4) the abdomen is cylindrical, the female is provided with a ventral ovipositor and has the terminal abdominal segment conical; the corresponding segment in the male is usually bluntly rounded.
These insects have the abdomen flattened, with its terminal segment (see fig.
probably due to a folding of the segment by which the two halves come to lie more or less parallel to each other, and form variously shaped figures of greater or less regularity (fig.
Some observers consider that it represents a longitudinal half of the original segment of the spireme, others that it is a half of the segment produced by transverse division by means of which a true qualitative separation of the chromatin is brought about.
The fifth abdominal segment has a pair of strong dorsal hook-like processes, by means of which the larva supports itself in the burrow which it excavates in the earth, the great head blocking the entrance with the mandibles ready to seize on any unwary insect that may venture within reach.
The Curculionidae, or weevils (q.v.), comprising 23,000 species, are by far the largest family of the group. The maxillary palps are short and rigid, and there is no distinct labrum, while the feelers are usually of an "elbowed" form, the basal segment being very elongate (figs.
In all ants the second (apparently the first) abdominal segment is very markedly constricted at its front and hind edges, so that it forms a "node " at the base of the hind-body (fig.
I), and in many ants the third abdominal segment is similarly " nodular " in form (fig.
- The head of an ant carries a pair of elbowed feelers, each consisting of a minute basal and an elongate second segment, forming the stalk or " scape," while from eight to eleven short segments make up the terminal " flagellum."
In the lastmentioned worm the funnels of the anterior nephridia are small and but few celled; it is only the nephridia in and behind the 17th segment of the body which are particularly large and with a sinuous margin, which recall the funnels of the gonad ducts (i.e.
The conversion of the posterior end of the simple individual into a sexual region is dispensed with; but from a preanal budding segment a series of sexual buds are produced.
Setae very rarely absent (genus Achaeta) and as a rule not so large or so numerous in e (.r, each segment as in the is Polychaeta, and different in shape.
In terrestrial A, Lumbricus : 9, to, segments contain ing spermathecae, the orifices of forms dorsal pores are usuwhich are indicated; 14, segment b ally present; in aquatic earing oviducal pores; 15, segforms a head pore only.
It has been shown (Bourne) that the "perichaetous" condition is probably secondary, inasmuch as in worms which are, when adult, "perichaetous" the setae develop in pairs so that the embryo passes through a stage in which it has four bundles of setae, two to each bundle, the prevalent condition in the group. Rarely there is an irregular disposition of the setae which are not paired, though the total number is eight to a segment (fig.
Ileymons, the hypopharynx represents the sterna of all the jaw-bearing somites, but other students consider that it belongs to the mandibular and first maxillary segments, or entirely to the segment of the first maxillae.
Ventrally, each segment of the thorax has a sternum with which a median pre-sternum and paired episterna and epimera are often associated (see figs.
A wing is an outgrowth from the dorsal and pleural regions of the thoracic segment that bears it, and microscopic examination shows it to consist of a double layer of cuticularized skin, the two layers being in contact except where they are thickened and folded to form the firm tubular nervures, which serve as a supporting framework for the wing membrane, enclose air-tubes, and convey blood.
Prominent paired limbs are often borne on the tenth segment, the elongate tail-feelers (cerci) of bristle-tails and may-flies, or the forceps of earwigs, for example.
- The nervous system in the Hexapoda is built up on the typical arthropodan plan of a double ventral nerve-cord with a pair of ganglia in each segment, the cords passing on either side of the gullet and connecting with an anterior nerve-centre or brain (fig.
A pair of ganglia in each thoracic segment is usual (fig.
The other is the segment of the maxillulae (see above, under Jaws), behind the mandibular somite; the presence of this in the embryo of the collembolan Anurida has been lately shown (1900) by J.
Riley holds that the hypopharynx be longs to the mandibular and maxillary segments, while the cervical sclerites 2 ---_,?1 N' ____ U1 or gula represent the ster Ant num of the labial segment.
The fact that there are two pairs of gonapophyses on the ninth abdominal segment would be fatal to the view that they are in any way homologous with legs, were it not that there is some evidence that the division into two pairs is secondary and incomplete.
But another and apparently insuperable objection may be raised - that the appendages of the ninth segment are the stylets, and that the gonapophyses cannot therefore be appendicular.
18, 5) belonging to the maxillular (or superlingual) segment, thus establishing seven sets of cephalic ganglia, and supporting his view as to the composition of the head.
Verhoeff has lately (1904) put forward the view that there are really six segments in the hexapodan thorax and twenty in the abdomen - the cerci belonging to the seventeenth abdominal segment thus showing a close agreement with the centipede Scolopendra.
Once the identity of the chilaria with the pentagonal sternal plate of the scorpion is recognized - an identification first insisted on by Lankester - the whole series of segments and appendages in the two animals, Limulus and Scorpio, are seen to correspond most closely, segment for segment, with one another (see figs.
Pocock of the British Museum has observed that in Limulus a marking exists on the fourth joint, which apparently indicates a previous division of this segment into two, and thus establishes the agreement of Limulus and Scorpio in this small feature of the number of segments in the legs (see fig.
I to IV, first to fourth appendages of the prosoma; a, basal segment of the second pair of appendages meeting its fellow in the middle line (see fig.
Appendages of 1st pair large, three segmented and completely chelate; of 2nd pair either simple and pediform, or prehensile and subchelate; of remaining four pairs, similar in form, ambulatory in function; the basal segment of the 2nd, 3rd and sometimes of the 4th pairs of appendages furnished with sterno-coxal (maxillary) lobe.
A, a segment of Bothriocephalus latus, showing the generative organs from the ventral surface; ex., excretory vessels; c., cirrus; c.p., cirrus pouch; v.d., vas deferens; v.o., vaginal opening; v., vagina; sh.g., shell-gland; od., oviduct; ov., ovary; y.g., yolk-gland; y.d., its duct; ut., uterus; u.o., uterine opening; the testes are not visible from this side; X 23 (from Sommer and Landois).
3, i.) with the metathorax, of which it often seems to form a part, the apparent first abdominal segment being, in such case, really the second (fig.
The typical insectan ovipositor, so well developed among the Hymenoptera, consists of three pairs of processes (gonapophyses) two of which belong to the ninth abdominal segment and one to After C. Janet, Aiguillon de la Myrmica rubra (Paris, 18g8).
5, A) of the ovipositor, while the two outer processes of the ninth segment are modified into sheaths or feelers (fig.
All the other families of Hymenoptera, including the gall-flies, ichneumons and aculeates, have the first abdominal segment closely united with the thorax, the second abdominal segment constricted so as to form a narrow stalk or " waist," and legless larvae without a hinder outlet to the food-canal.
II) have feelers with seven or fewer distinct segments, and the fifth abdominal From Osb orn (after segment usually carries a pair of tubular proSchibdte), Bull.
He showed that the surface of a segment is equal to the area of the circle whose radius equals the distance from the vertex to the base of the segment; that the surface of the entire sphere is equal to the curved surface of the circumscribing cylinder, and to four times the area of a great circle of the sphere; and that the volume is twothirds that of the circumscribing cylinder.
The eleventh abdominal segment which carries the short jointed cerci (fig.
apis), a large and natural family of the zoological order Hymenoptera, characterized by the plumose form of many of their hairs, by the large size of a the basal segment of the foot, which is always elongate and in the hindmost limb sometimes as broad as the shin, and by the development of a "tongue" for sucking liquid food; this organ has been variously interpreted as the true insectan tongue (hypopharynx) or as a ligula formed by fused portions of the second maxillae (probably the latter).
If we mark off a segment AB along the line of action so as to represent the force completely, the A moment is represented as to magni FIG 15 tude by twice the area of the triangle OAB, and the usual convention as, .o sign is that the area is to be reckoned positive or negative iccording as the letters 0, A, B, occur in counter-clockwise or clockwise order.
The penultimate segment is often broadened, so that the terminal claw shuts against a transverse edge (fig.
In the latter class we should distinguish three phases: (a) those with numerous and comparatively undeveloped rami; (b) those with three, or two highly developed rami, or with only one - the corm being reduced to the dimensions of a mere basal segment; (c) those reduced to a secondary simplicity (degeneration) by overwhelming development of one segment (e.g.
In the Quadrature of the parabola Archimedes finds the area of a segment of a parabola cut off by any chord.
A single nucleotide change in the c-myc internal ribosome entry segment leads to enhanced binding of a group of protein factors.
Large runabout segment (20 to 29 feet) Cobalt ranks highest in the large runabout segment for a fifth consecutive time.
Diarrhea may occur temporarily especially if a long segment of ileum is used.
Dewey played safe and waged a non-committal campaign designed to avoid offending any segment of the electorate.
When you are trying to find only the best segment of similarity between two sequences, use BestFit.
Programmer 's Notes: This function will fail if the selector specified in BX is not a code segment or is invalid.
Move any segment which gives a smaller distance to the sibling node than its own node.
Segment registers and the stack pointer will not be passed between modes.
CONCLUSION: Endovascular stent grafting of the femoral segment is a straightforward procedure in selected patients.
The silk is produced from special glands in the swollen tarsal segment on each front leg.
The kinase phosphorylates the CDKs on a threonine residue which lies within the activation segment, a modification essential for generating kinase activity.
Plks have a threonine in the activation segment whose phosphorylation is essential for activity.
Road Segment and Area Avoidance Would you like to avoid traffic tie-ups or roadwork?
The segment of tourism undergoing the fastest growth is nature-based tourism, which includes ecotourism (WTTC, 2000).
Identify the aromatic residue near each end of the transmembrane segment.
The solution is to deploy the anonymous access WAP on a perimeter network segment that does not have access to the corporate network.
Most people have seen a segment of QVC even if they are not interested in shopping via the television.
Actually, the white wiggling part is just a segment that breaks to form a new worm, rather than the original worm itself, but that's probably more than you ever wanted to know.
The first method is typically easier to read since you are focusing on one segment at a time, and you can easily return to the point where you left off by simply following the correct link.
There is also a large segment of the populous that is vegetarian, and many restaurants will only serve vegetarian meals.
Organic foods are the fastest growing segment of our agricultural economy.
Just like any large group of people, it can be difficult to make generalizations about this segment of the population.
Regardless of your preference, make sure you pair the right reading with the right segment of the wedding.
Another option is serving each slice with an orange segment.
Place a plump berry or fresh segment of fruit on each cupcake.
His first visit was so popular that Oprah created a weekly segment around him, giving him the title of Relationship and Life Strategy Expert.
The interview lasted about six minutes, and Khloe's nipple was on display for the majority of the segment.
She began doing a weekly cooking segment on the local CBS affiliate, made a public radio appearance, and released her first book, which sold 10,000 copies locally.
Her first national appearance was a segment on the Today Show.
These semi-finalists are eventually whittled down to four finalists, who must present a commercial segment of their inventions.
Only one segment aired, but it landed him a trial job corresponding for The Daily Show in 1997, during the show's second season.
As a result, the actress appeared in a segment for the show where she shopped for and modeled a bikini.
He took a few other digs at Montag, and was done with his segment - or so he thought.
LTK: Your NY1 segment, In the Papers, is a favorite for viewers.
It's the same concept as the NY1 In the Papers segment, delivered as a daily list of favorite stories from U.S. newspapers.
Short cruises are the fastest growing segment of the cruise industry.
They also have curtains that can segment the room, so parents can stay up without disturbing sleeping children.
Joke messages prevail, although political commentary seems to be a fast-growing segment.
Nowadays, designer jeans and shorts from Gap, CK, Tommy Hilfiger, True Religion, Polo Ralph Lauren and DKNY are becoming a significant and profitable segment in the industry.
After a little digging, it was discovered that the study was based on two women, the entire female segment of the student body.
In the past, shopping for plus size women's clothing was frustrating and time consuming because few clothing manufacturers catered to this segment of the population.
Because the largest segment of the American population, the Baby Boomers are growing up, getting older, and wanting their Social Security funds.