Anterior sentence example
The anterior end of body always shows some "cephalization."
The most important of these opens by the ventral pedal pore, situated in the median line in the anterior half of the foot.
When the pericardium is cut open from above in an animal otherwise entire, the anterior face of the kidney is seen forming the posterior wall of the pericardial chamber; on the deep edge of this face, a little to the left of the attachment of the auricle to the floor of the pericardium, is seen a depression; this depression contains the opening from the pericardium into the kidney.
Animal fixed by the shell, the last whorls of which are not in contact with each other; foot small; two anterior pedal tentacles.
Visceral sac and shell coiled in one plane; foot divided transversely into two parts, posterior part bearing an operculum, anterior part forming a fin provided with a sucker.Advertisement
Thus the base of the gill passes in a slanting direction across the right-hand side of the kidney, the posterior end being dorsal to the apex of the gland, and the anterior end ventral to the right-hand corner.
Anterior part of the foot underlying the head.
They are all pelagic, the foot being entirely transformed into a pair of anterior fins; eyes are absent, and the nerve centres are concentrated on the ven tral side of the oesophagus.
The middle valley is often intersected by vertical "crista" and "crochet" plates projecting into it from the anterior surface of the posterior transverse ridge or from the wall, the development of which is a useful guide in discriminating species, especially those known only by teeth and bones.
The different parts of the wing, moreover, travel at different degrees of velocity - the tip and posterior margin of the wing always rushing through a much greater space, in a given time, than the root and anterior margin.Advertisement
The biceps brachii is anterior to the humerus in an equivalent position to the biceps brachii is anterior to the humerus in an equivalent position to the biceps muscle in the human arm.
The next six families include the animals formerly known as Gymnosomatous Pteropods, characterized by the absence of mantle and shell, the reduction of the ventral surface of the foot, and the parapodial fins at the anterior end of the body.
Shell external and conical; anterior tentacles form a frontal veil; ctenidium extending only over right side; a distinct osphradium.
Shell external, conical, much flattened; anterior tentacles very small, and situated with the mouth in a notch of the foot below the head; ctenidium very large.
Shell covered by mantle, or absent; anterior tentacles form a frontal veil; mantle contains spicules.Advertisement
Anterior tentacles form a frontal veil; foot rather broad.
No anterior tentacles, and no dorsal appendages; body laterally compressed, transparent; pelagic. Phyllirhoe.
Anterior tentacles forming a scalloped frontal veil; dorsal appendages and tentacles similarly ramified.
Mantle-border projecting; frontal veil reduced, and often covered by the anterior border of the mantle.
Mantle oval, covering the head and the greater part of the body; anterior tentacles,.Advertisement
The foot now protrudes below the mouth, and the post-oral hemisphere of the trochosphere grows more rapidly then the anterior or velar area.
Shell internal, or absent; mantle restricted to the anterior and middle part of the body; radula with squarish teeth.
Anterior tentacles much reduced; male and female apertures contiguous but distinct; shell thin,.
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.
Below each eye is a cheek area (gena), often divided into an anterior and a posterior part, while a distinct chin-sclerite (gula) is often developed behind the mouth.Advertisement
Carriere's researches (1897) on the make its appearance simultaneously throughout the whole length of embryology of the mason bee (Chalicodoma) agree entirely with the the plate; the anterior parts are segmented before the posterior.
He finds that the endoderm arises may be readily distinguished, six of which subsequently enter into from an anterior and a posterior rudiment derived from the " endothe formation of the head, three going to the thorax and twelve to blast," that many of the cells of these rudiments wander into the the abdomen.
From these facts it appears that the anterior three divisions of the head differ strongly from the posterior three, which greatly resemble thoracic segments; hence it has been thought possible that the anterior divisions may represent a primitive head, to which three segments and their leg-like appendages were subsequently added to form the head as it now exists.
The nervous system of the embryonic head exhibits three ganglionic masses, anterior to the thoracic ganglionic masses; these three masses subsequently amalgamate and form the sub-oesophageal ganglion, which supplies the trophal segments.
In front of the three masses that will form the sub-oesophageal ganglion the mass of cells that is to form the nervous system is very large, and projects on each side; this anterior or " brain " mass consists of three lobes (the prot-, deut-, and tritencephalon of Viallanes and others), each of which might be thought to represent a segmental ganglion.
There are other ganglia in addition to those of the ventral chain, and Janet supposes that the ganglia of the sympathetic system indicate the existence of three anterior head-segments; the remains of the segments themselves are, in accordance with this view, to be sought in the XIII.
But the latter used this privilege wisely and well-not, after the manner of De Blainville and others subsequent to him, relying solely or even chiefly on the character afforded by the posterior portion of the sternum, but taking also into consideration those of the anterior, as well as of the in some cases still more important characters presented by the pre-sternal bones, such as the furcula, coracoids and scapulae.
But it was now made to appear that the struthious birds in this respect resembled, not only the duck, but a great many other groups - waders, birds-of-prey, pigeons, passerines and perhaps all birds not gallinaceous - so that, according to Cuvier's view, the five points of ossification observed in the Gallinae, instead of exhibiting the normal process, exhibited one quite exceptional, and that in all other birds, so far as he had been enabled to investigate the matter, ossification of the sternum began at two points only, situated near the anterior upper margin of the side of the sternum, and gradually crept towards the keel, into which it presently extended; and, though he allowed the appearance of detached portions of calcareous matter at the base of the still cartilaginous keel in ducks at a certain age, he seemed to consider this an individual peculiarity.
These nine theoretical centres or " pieces " L'Herminier deemed to be disposed in three transverse series (rangees), namely the anterior or " prosternal," the middle or " mesosternal " and the posterior or " metasternal " - each series consisting of three portions, one median piece and two side-pieces.
These laws, as formulated by him, are that (1) there is a coincidence of form of the anterior palatal and of the cranium in birds of the same order; (2) there is a likeness between the anterior palatal bones in birds of the same order; (3) there are relations of likeness 1 The title of the English translation is Johannes Muller on Certain Variations in the Vocal Organs of the Passeres that have hitherto escaped notice.
These laws, he added, exist in regard to all parts that offer characters fit for the methodical arrangement of birds, but it is in regard to the anterior palatal bone that they unquestionably offer the most evidence.
Be that as it may, he declares that characters drawn from the sternum or the pelvis - hitherto deemed to be, next to the bones of the head, the most important portions of the bird's framework - are scarcely worth more, from a classificatory point of view, than characters drawn from the bill or the legs; while pterylological considerations, together with many others to which some systematists had attached more or less importance, can only assist, and apparently must never be taken to control, the force of evidence furnished by this bone of all bones - the anterior palatal.
At the same time he states that authors who have occupied themselves with the sternum alone have often produced uncertain results, especially when they have neglected its anterior for its posterior part; for in truth every bone of the skeleton ought to be studied in all its details.
There are two dorsal fins, the anterior near the head, composed of 11-14 feeble spines, the second near the tail with all the rays soft except the first, and behind the second dorsal five or six finlets.
At the circular insertion of the proboscis in front of the brain the muscular fibres belonging to the anterior extremity of the body and those connected with the proboscis are very intimately interwoven, forming a strong attachment.
The brain must be opening; u.l, superior brainlooked upon as the anterior thicklobe; pl., posterior brain-lobe.
In Carinella this separation into lobes of the anterior thickenings of the cords has not yet commenced, the ventral commissure at the same time being extremely bulky.
It stretches forward as far as the brain, and in Carinella is again continued in front of it, whereas in the Heteronemertines the innervation of the anterior extremity of the head, in front of the brain, takes the form of more definite and less numerous branching stems. The presence of this plexus in connexion with the central stems, sending out nervous filaments amongst the muscles, explains the absence, in Pro-, Mesoand Heteronemertines, of separate and distinct peripheral nerve stems springing from the central stems innervating the different organs and body-regions, the only exceptions being the L.N.
The more highly organized species have often very numerous eyes (Amphiporus, Drepanophorus), which are provided with a spherical refracting anterior portion, with a cellular " vitreous body," with a layer of delicate radially arranged rods, with an outer sheath of dark pigment, and with a separate nerve-twig each, springing from a common or double pair of branches which leave the brain as n.
The anterior opening, the mouth, is situated ventrally, close to the tip of the head and in front of the brain in the Metanemertini, somewhat more backward and behind the brain in the other Nemertines.
The oesophagus is the anterior portion of the digestive canal; its walls are folded longitudinally, comparatively thick and provided with longitudinal muscular fibres.
They are in direct connexion with each other both at the posterior and at the anterior end of the body.
As a rule these organs only extend a short way along the anterior end of the body, a concentration which we may associate with the development of a vascular system I--- to bring the products of excretion to a fixed spot.
They are cylindrical worm-like animals, with a median anterior mouth quite devoid of any armature or tentacles.
The treatises are nearly all anterior to the 7th century, and most appear to belong to the 3rd and 4th centuries; some are the work of authentic authors like Zosimus and Synesius, while of others, such as profess to be written by Moses, Democritus, Ostanes, &c., the authorship is clearly fictitious.
Its integument is marked by a large number of transverse grooves simulating the segmentation of Annelids, and near the anterior extremity close to the mouth are two pairs of recurved chitinous hooks.
The nervous system is represented by an oesophageal collar and a suboesophageal ganglion, whence paired nerves pass outwards to innervate the anterior extremity and backwards towards its posterior end.
In the female the ovary is a large unpaired organ from the anterior end of which arise two oviducts, and connected with the latter are a pair of large so-called copulatory pouches, which perhaps act as receptacula seminis.
The entire body behind the shoulder-blades is uniformly coloured, with the exception of the feet; the anterior part of the body, including the fore legs, neck, and jaws, is white, the cheeks and ears being coloured.
Interment in rock-hewn tombs, " as the manner of the Jews is to bury," had been practised in Rome by the Jewish settlers for a considerable period anterior to the rise of the Christian Church.
First upper premolar with a triangular crown narrow in front owing to the absence of the anterior inner column.
The other upper premolars and molars all formed on the same plan and of nearly the same size, with four roots and quadrate crowns, rather wider transversely than from before backwards, each having four columns, connected by a pair of transverse ridges, anterior and posterior.
The first lower premolar compressed in front; the others composed of a single pair of transverse crests, with a small anterior and posterior basal ridge.
Usually it passes from the throat (the anterior part of which, with the whole of the under jaw, is dark) above the origin of the flipper, along the middle of the flank, and descends again to the middle line before reaching the tail.
The dorsal skeletal elements of the thorax and of the anterior six abdominal segments unite with the wing-cases to form a large respiratory chamber, containing five pairs of tracheal gills, with lateral slits for the inflow and a posterior orifice for the outflow of water.
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.
There are reasons for supposing that the truncal coelom was at one time provided with pore-canals, but supposed vestiges of these structures have only been described for one genus, Spengelia,in which they lie near the anterior end of the truncal coelom.
The proboscis-gut occurs as an outgrowth from the anterior dorsal wall of the collar-gut, and extends forward into the basal (posterior) region of the proboscis, through the neck into the proboscis-coelom, ending blindly in front.
The nervous system is thus essentially epidermal in position and diffuse in distribution; but an interesting concentration of nerve-cells and fibres has taken place in the collar-region, where a medullary tube, closed in from the outside, opens in front and behind by anterior and posterior neuropores.
These gill-slits occupy a variable extent of the anterior portion of the trunk, commencing immediately behind the collartrunk septum.
It seems likely that the coelomic pore-canals were originally excretory organs, but in the existing Enteropneusta the pore-canals (especially the collar canals) have, as we have seen, acquired new functions or become vestigial, and the function of excretion is now mainly accomplished by a structure peculiar to the Enteropneusta called the glomerulus, a vascular complex placed on either side of the anterior portion of the stomochord, projecting into the proboscis-coelom.
It is within the bounds of possibility that Tornaria actually does indicate a remote affinity on the part of the Enteropneusta to the Echinoderms, not only on account of its external form, but also by reason of the possession of a dorsal water-pore communicating with the anterior body-cavity.
The anterior half of this space is lined by the inner wall of the mantle and is called the mantle cavity.
The mouth lies in the centre of the anterior wall of the body.
The intestine is slung by a median dorsal and ventral mesentery which divides the body cavity into two symmetrically shaped halves; it is " stayed " by two transverse septa, the anterior or gastroparietal band running from the stomach to the body wall and the posterior or ileoparietal band running from the intestine to the body wall.
In Rhynchonella, where there are two pairs of kidneys, the internal opening of the anterior pair is supported by the gastroparietal band and that of the posterior pair by the ileoparietal band.
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 mouth is terminal and anterior and surrounded by a ring of spicules or a half-ring of hooks.
This lies in the anterior part of a groove fringed with hairs on the inferior petal.
The various comparisons previously made between the structure of Limulus and the Eurypterines on the one hand, and that of a typical Arachnid, such as Scorpio, on the other, had been vitiated by erroneous notions as to the origin of the nerves supplying the anterior appendages of Limulus (which were finally removed by Alphonse Milne-Edwards in his beautiful memoir (6) on the structure of that animal), and secondly by the erroneous identification of the double sternal plates of Limulus, called " chilaria," by Owen, with a pair of appendages (7).
The Composition of the Head (that is to say, of the anterior part of the prosoma) with especial Reference to the Region in Front of the Mouth.
But although in such lower Crustacea the nerve-ganglia of the third prosthomere have not fused with the anterior nerve-mass, there is no question as to the prae-oral position of two appendage-bearing somites in addition to the ocular prosthomere.
In Scorpio the completion of the horizontal plate by oblique flaps, so as to form an actual diaphragm shutting off the cavity of the prosoma from the rest of the body, possibly gives to the organs contained in the anterior chamber a physiological advantage in respect of the supply of arterial blood and its separation from the venous blood of the mesosoma.
The seventh, VII, is anterior to the genital operculum, op, and is the cavity of the praegenital somite which is more or less completely suppressed in subsequent development, possibly indicated by the area marked VII in fig.
Scorpio certainly comes nearer to Limulus in the high development of its arterial system, and the intimate relation of the anterior aorta and its branches to the nerve centres and great nerves, than does any other Arthropod.
The figure B also shows the peculiar neural investiture formed by the cerebral arteries in Limulus and the derivation from this of the arteries to the limbs, III, IV, VI, whereas in Scorpio the latter have a separate origin from the anterior aorta.
There is some reason to admit the existence of another more anterior pair of these muscles in Scorpio; this would make the number exactly correspond with the number in Limulus.
This would lead to the supposition that the great development of metasomatic carapace is a primitive and not a late character, were it not for the fact that Paradcxides and Atops, with an inconspicuous telsonic carapace and numerous free somites, are also Cambrian in age, the latter indeed anterior in horizon to Agnostus.
Excalation of one or of two anterior mesosomatic somites, besides the prae-genital somite, would then have to be supposed to have occurred also.
There is also a pair of narrow tergal sclerites interposed between the anterior and posterior shields.
Between the bases of the prosomatic limbs an anterior III and a posterior sternal plate (black) are seen.
The posterior pulmonary sacs (except in Hypochilus) replaced by tracheal tubes; the anterior and posterior pairs replaced by tracheal tubes in the Caponiidae.
A, Ventral view of prosoma and of anterior region of opistho soma with the appendages cut off near the base; a and b, B, Dorsal view.
Opisthosoma confluent throughout its breadth with the prosoma, with the dorsal plate of which its anterior tergal plates are more or less fused; at most ten opisthosomatic somites traceable; the generative aperture thrust far forwards between the basal segments of the 6th appendages.
The body is stout and thickly built; the legs are short and strong, and armed, especially the anterior pair, with long curved claws; the tail is short; and the ears are reduced to rudiments.
Since, then, the existence of separate books of psalms anterior to the present divisions of the Psalter is very doubtful, we must look for other evidences of date.
His body was buried in the church 1 This letter, even if spurious as now suspected, is found in the 11th-century Leiden MS., and is therefore anterior to the first crusade.
It met from the 3rd of May 1512 to the 16th of March 1517, and was the last great council anterior to the Reformation.
In the case of the squamous epithelial cancer of the anterior abdominal wall found so frequently in the natives of Kashmir, the position of the cancer is peculiar to this people, and is due to the chronic irritation following on repeated burns from using the " kangri " - a small earthenware vessel containing a charcoal fire enclosed in basket-work, and suspended round the waist, to assist in maintaining warmth in the extreme cold of the hills of Kashmir.
The contorted strata of slate and greywacke rock must have been formed at a period vastly anterior to that in which the lake of the upper valley managed to force an outlet through the enclosing barriers.
Thus all historians are agreed with regard to the Babylonian chronology back to the year 747 B.C., and with regard to that of Assyria back to the year 911 B.C. It is in respect of the periods anterior to these two dates that different writers have propounded differing systems of chronology, and, as might be imagined, the earlier the period we examine the greater becomes the discrepancy between the systems proposed.
The anterior third of the body is attenuated and sharply marked off from the bulbous trunk in Didymozoon.
The mouth lies usually in the centre of the anterior vzs and sub-terminal sucker or between two adoral suckers, but in Gasterostomum and its allies it is mid-ventral.
The anterior and posterior ends of the body are well defined.
In Distomum acanthocephalum the cuticle forms circlets of large and small hooks at the anterior end, somewhat as in Cestodes.
A, Fasciola hepatica, from the ventral surface (X 2); the alimentary and nervous systems only shown on the left side of the figure, the excretory only on the right; a, right main branch of the intestine; c, a diverticulum; g, lateral ganglion; n, lateral nerve; o, mouth; p, pharynx; s, ventral sucker; cs, cirrus sac; d, left anterior dorsal excretory vessel; m, main vessel; v, left anterior ventral trunk; x, excretory pore.
Lastly the nervous system is well developed and consists of a pair of well-marked and interconnected ganglia placed near the anterior end and dorsal to the oesophagus.
It is posterior (Amphistomidae), or anterior (Gasterostomidae).
In addition to these suckers the sides of the anterior region may become infolded and give rise to an accessory adhesive organ (Holostomidae).
Numerous places in the valley of the Main are mentioned in chronicles anterior to the time that Frankfort is first noticed.
In the 13th century, the Frankfort Fair, which is first mentioned in 1150, and the origin of which must have been long anterior to that date, is referred to as being largely frequented.
The hinder portion of the body being drawn of ter, some part of it (c) finds another support on the rough ground or a projection; and, the anterior bends being stretched in a straight line, the front part of the body is propelled (from a to d) in consequence.
Some snakes can raise the anterior part of their body and even move in this attitude, but it is only about the anterior fourth or third of the total length which can be thus erected.
The anterior maxillary teeth are grooved or "perforated."
In another, probably also egg-eating snake, the Indian teeth, hence the term "proteroglypha," which is intended to mean that the anterior teeth are grooved.
Doliophis intestinalis of Indo-China has enormously developed poison glands, which extend down the whole anterior third of the body, in front of the heart.
Several species are remarkable for the extremely slender and prolonged anterior part of the body, and very small head.
There are also teeth on the palatines, anterior portion of the pterygoids, and on the short dentaries.
The poison-fangs are "solenoglyphous," perforated, having a wide hole on the anterior side at the base, in connexion with the duct of the large, paired, poison-glands, the presence of which adds considerably to the characteristic broadness of the head.
The insect is fixed by this rostrum, which is inserted into the root of the vine for the purpose of sucking the sap. The abdomen consists of seven segments, and these as well as the anterior segments bear four rows of small tubercles on their dorsal surface.
The anterior pair reach far beyond the end of the abdomen; the posterior are narrower and not so long.
Other modifications are the loss of the upper incisors; the development of the canines into projecting tusks; and the loss of the anterior premolars.
The cheek-teeth are selenodont, and one pair of upper incisors is retained, while some of the anterior premolars assume a canine-like shape, and are separated from the rest of the cheekseries.
The High Churchman of the "Catholic" type is further differentiated from the "oldfashioned High Churchman" of what is sometimes described as the "high and dry" type of the period anterior to the Oxford Movement.
His sympathies, however, were always with mechanical and scientific pursuits, and several of his inventions date from a time anterior to his final abandonment of the law.
The lines of cardinal importance are (I) the rasceta or cross sulci, which isolate the hand from the forearm at the wrist, and which are the flexion folds between the looser forearm skin and that tied down to the fascia above the level of the anterior annular ligament.
In southern Italy, probably under Greek influence, and in Milan (where the custom still survives) the diaconal stole was put on over the dalmatic. Similarly in Spain and Gaul, anterior to the Carolingian age, the stole was worn by deacons over the alba or outer tunic.
At some date long anterior to history it is supposed that Indo-China was occupied first by a fair Caucasian people and later by a yellow Mongolian race.
Such a complete reduction of the whole anterior limb and girdle is unique among birds, but the cassowaries indicate the process.
The hind limbs are very strong; the massive femur has a large pneumatic foramen; the tibia has a bony bridge on the anterior surface of the lower portion, a character in which the moas agree only with Apteryx amongst the other Ratitae.
The initial values of T, S, D, I, A must be accepted as belonging to the anterior portion of the table.
Like "Brazil," it dates from a period anterior to the discovery of the New World, "Antilia," as stated above, being one of those mysterious lands, which figured on the medieval charts sometimes as an archipelago, sometimes as continuous land of greater or lesser extent, constantly fluctuating in mid-ocean between the Canaries and East India.
The heart has a pair of venous ostia, often blending into one, and an anterior arterial aorta.
The posterior end of the organ is positive, the anterior negative, and the current, passes from the tail to the head.
Early Christian tradition is unanimous on this side; either the 14th is mentioned, or the Crucifixion is made the antitype of the slaughter of the Paschal Lamb (and the Resurrection of the first fruits), in the following authorities anterior to A.D.
The foot is very large and powerful; it can be protruded from the anterior aperture between the mantle edges, and its outer part is bent sharply forwards and terminates in a point.
The tongue is generally beset with more or less scaly or velvety papillae and has always a well-marked posterior margin, while the anterior portion may or may not be more or less retractile into the posterior part.
Both as regards structure and habits, the leopard may be reckoned as one of the more typical representatives of the genus Felis, belonging to that section in which the hyoid bone is loosely connected with the skull, owing to imperfect ossification of its anterior arch, and the pupil of the eye when contracted under the influence of light is circular, not linear as in the smaller cats.
The ventral fins are slightly anterior to the origin of the dorsal fin; and the spine consists of from fortyseven to forty-nine vertebrae.
In the majority of Trilobites this groove passes backwards from the anterior or anterolateral edge of this plate to its posterior or postero-lateral border, dividing it into an inner portion continuous with the flabellum and fused tergal regions, and an outer portion bearing the eye.
The end by which the parasites join is typically, in the case of Trypanosoma, the non-flagellate (anterior) end.
Hence in this genus the end bearing the free part of the flagellum is the anterior one.
The genus Trypanosoma, in which are included at present the great majority of Trypanosomes, is rather to be regarded as derived from a Heteromastigine ancestor, such as Trypanoplasma, by the loss of the anterior flagellum.
The other, the anterior flagellum, may or may not persist.
Both flagella are inserted close together, near the anterior end of the body.
The anterior flagellum is longer than the free part of the posterior one.
The point of insertion of the attached (posterior) flagellum into the body, and, consequently, the commencement of the undulating membrane may be almost anywhere in the anterior half of the body, but is usually near the extremity.
Uranus and other Greek gods anterior to Zeus were probably deities worshipped by earlier barbarous inhabitants of the land.
When hardened in situ its shape is that of a right-angled, triangular prism showing five surfaces - superior, anterior, inferior, posterior and right lateral which represents the base of the prism.
At its posterior margin the peritoneum of the great sac is reflected on to the diaphragm to form the anterior layer of the coronary ligament.
The anterior surface is in contact with the diaphragm and the anterior abdominal wall.
Again starting from the right side, two impressions are seen; the anterior one is for the hepatic flexure of the colon, and the posterior for the upper part of the right kidney.
When the edges of the mantle ventral to the inhalant orifice are united, an anterior aperture is left for the protrusion of the foot, and thus there are three pallial apertures altogether, and species in this condition are called " Tripora."
It is the approximate equality in the size of the anterior and posterior adductor muscles which led to the name Isomya for the group to which Anodonta belongs.
The hinder adductor muscle is always large in Lamellibranchs, but the anterior adductor may be very small (Heteromya), or absent altogether (Monomya).
In fact all Lamellibranchs begin with a condition in which there is only one adductor, and that not the posterior but the anterior.
Then the posterior adductor develops, and becomes equal to the anterior, and finally in some cases the anterior becomes smaller or disappears.
The single adductor muscle of the Monomya is separated by a difference of fibre into two portions, but neither of these can be regarded as possibly representing the anterior adductor of the other Lamellibranchs.
Their appearance and position suggest that they are in some way related morphologically to the gill-plates, the anterior labial tentacle being a continuation of the outer gill-plate, and the posterior a continuation of the inner gill-plate.
In the same figure the free part of the inner lamella of the inner gill-plate resting on the foot is marked z, whilst the attached parjt - the most anterior - has been snipped with scissors so as to show the genital and nephridial apertures x and y.
The arrows ac, Anterior.
Formerly the posterior pair of ganglia were identified as simply the osphradial ganglia, and the anterior pair as the cerebral, pleural and visceral ganglia united into a single pair.
This byssus is not homologous with that of other Lamellibranchs, but originates from a single glandular epithelial cell embedded in the tissues on the dorsal anterior side of the adductor muscle.
The glochidium is formed by the precocious development of the anterior adductor and the retardation of all the other organs except the shell.
At the anterior end of the test is the apical plate from the centre of which projects a long flagellum as in many other Lamellibranch larvae.
The Pseudolamellibranchia included the oyster, scallop and their allies which formerly constituted the order Monomyaria, having only a single large adductor muscle or in addition a very small anterior adductor.
Symmetrical; mantle open throughout its extent; generally with well developed anterior and posterior adductors.
Philobryidae.-Shell thin, very inequilateral, anterior part atrophied, umbones projecting.
Heart gives off only an anterior aorta.
Pernidae.-Shell very inequilateral; ligament subdivided; mantle open throughout; anterior adductor absent.
The last two families are dimyarian, with small anterior adductor.
A remarkable feature is the frequent concrescence of mesothorax and metathorax and in some cases, even, their fusion with the anterior abdominal segments.
The business was continued by his sons Georg (1804-1884) it as layer of cubical cells, which are continuous near the anterior border with the cells of the peritoneum.
The upper half or body of the uterus is somewhat triangular with its base upward, and has an anterior surface which is moderately flat, and a posterior convex.
The canal of the cervix is about an inch long, and is spindle-shaped when looked at from in front; its anterior and posterior walls are in contact, and its lining mucous membrane is raised into a pattern which, from its likeness to a cypress twig, is called the arbor vitae.
The vagina is a dilatable muscular passage, lined with mucous membrane, which leads from the uterus to the external generative organs; its direction is, from the uterus, downward and forward, and its anterior and posterior walls are in contact, so that in a horizontal section it appears as a transverse slit.
Owing to the fact that the neck of the uterus enters the vagina from in front, the anterior wall of that tube is only about 21 in., while the posterior is 31.
The prostatic urethra runs downward through the prostate rather nearer the anterior than the pos terior part.
Its more pointed lower end iš attached to the uterus by the ligament of the ovary, while its anterior border has a short reflection of peritoneum, known as the mesovarium, running forward to the broad ligament of the uterus.
It is through this anterior border that the vessels and nerves enter and leave the gland.
The spongy urethra is that part which is enclosed in the penis after piercing the anterior layer of the triangular ligament.
At the anterior end the head is differentiated; it bears the sense-organs, and contains the muscular pharynx within which is the radular apparatus.
In the primitive form a single anterior aorta is given off from the ventricle, the two together representing the dorsal blood-vessel of Chaetopods.
The mouth is divided into two cavities communicating by a narrow orifice, the anterior one containing the incisors and the posterior the molars, the hairy skin of the face being continued inwards behind the incisors.
The digastric muscles also are remarkable for their well-defined central tendon, and in many species their anterior bellies are united between the two halves of the lower jaw.
The expanded anterior root of the zygomatic process has its front border oblique.
Associated with this is the strength and sharpness of the lower jaw, the prominence and anterior pcsition of the masseteric ridge, and the depth of the ramus from the alveolar line to the angle.
But the influence of the alkaloid upon the spinal cord is very marked and characteristic. The reflex functions of the cord are entirely abolished, and it has been experimentally shown that this is due to a direct influence upon the cells in the anterior cornua.
The "Boeotian" population seems to have entered the land from the north at a date probably anterior to the Dorian invasion.
It is possible that he took refuge at Benevento when Pavia was taken by Charlemagne in 774, but it is much more likely that his residence there was anterior to this event by several years.
Spadella P. Langerhans, with a pair of lateral fins on the tail and a thickened ectodermic ridge running back on each side from the head to the anterior end of the fin.
Professor Poulton long ago suggested, and supported the suggestion by experimental evidence on a lizard, that the larvae of two British species, C. elpenor and C. porcellus, are protected by the resemblance to the heads of snakes presented by the anterior extremities of their bodies which are ornamented with large eye-like spots.
When the larvae are disturbed the similarity is produced with startling suddenness by the telescopic contraction of the anterior segments in such a manner as to suggest a triangular, pointed head with two large dorsal eyes.
Finally Shelford states that the anterior end of a Bornean species (C. myodon) offers a striking and detailed resemblance to the head of a snake (Dendrophis pitta).
In this case also the posterior end of the larva represents the anterior end of the ant.
The wings are transparent and are black-bordered and black-barred, the anterior wing having two black bars and the posterior one.
Narrowing of the posterior portions of the spider's cephalothorax and sometimes of the anterior end of the abdomen reproduces the slender waist of the ant, and frequently transverse bands of hairs represent the segmentation of this region in the insect.
His name has been attached to a Liber Sacramentorum anterior to that of St Gregory, but he can have composed only certain parts of it.
As to the so-called Decretum Gelasii de libris recipiendis et non recipiendis, it also is a compilation of documents anterior to Gelasius, and it is difficult to determine Gelasius's contributions to it.
The anterior margin of each valve except the first is provided with two projections called sutural laminae which underlie the posterior margin of the preceding valve.
The eyes are arranged in rows running diagonally from the median anterior beak.
Each gill has the structure of a typical molluscan ctenidium, consisting of an axis bearing an anterior and posterior row of filaments or lamellae.
The gonad is transversely wrinkled and lies between the aorta and the intestine, extending from the pericardium to the anterior end of the body.
A simple gonaduct on each side arises from the gonad near its posterior end and passes first forwards, then backwards, and lastly outwards to the external opening in the pallial groove, anterior to the renal aperture.
The openings of the auricles into the ventricle vary in different forms. In many of the lower forms (Lepidopleuridae, Mopalidae, Ischnochitonidae) the opening on each side is single and anterior.
The ventricle leads into a single anterior median aorta.
From the points where the cords meet the cerebral commissure, arise on each an anterior labial commissure and a stomatogastric commissure.
The gonads originate by proliferation of the anterior wall of the pericardium.
The gonads are paired and hermaphrodite, they form a pair of anterior prolongations of the pericardium, extending nearly to the anterior end of the body.
The anterior extremity is also somewhat enlarged.
The mouth is anterior, terminal and crescentic, and beneath it is a rounded ventral shield.
It has long been conceded that the great French national epics of the 11th and 12th centuries must have been founded on a great fund of popular poetry, and that many of the episodes of the chansons de geste refer to historical events anterior to the Carolingian period.
In colour the sides of the face are puce, and the neck and most of the body purplish, but the buttocks and upper part of both fore and hind limbs are transversely barred with black and white, while their lower portion is mainly white with black fetlock-rings, and in the front pair a vertical black stripe on the anterior surface.
Although toad-like it is not really related to the toads proper, but belongs to the family Discoglossidae, characterized by a circular, adherent tongue, teeth in the upper jaw and on the palate, short but distinct ribs on the anterior vertebrae, and convex-concave vertebrae.
The criminal code, based Cases t on that of Prussia anterior to 1870, was ear.
The new Index, which omits works anterior to 1600 as well as a great number of others included in the, old catalogue, appeared in 1900.
The vent is below the anterior half of the first dorsal fin.
The anterior one-quarter or one-third of the body is capable of being retracted into the remainder, as the tip of a glove-finger may be pushed into the rest, and this retractile part is termed the introvert.
Much of these texts is of extreme antiquity; one incantation at least has been proved to belong to an age anterior to the unification of the Northern and Southern kingdoms. Later copies also exist, but possess little independent critical value.
The thallus is somewhat spherical and unicellular, exhibiting a distinction between anterior and posterior extremities, and dorsal and ventral surfaces.
In the lower jaw the first molar has 7 prisms, of which the 3 anterior are generally not fully separated from one another, the second 5 and the third 3.
The crowns of the molars belong to the crescentic or selenodont type, and are tall-crowned or hypsodont; but one or more of the anterior premolars is usually detached from the series, and of simple pointed form.
The neck is long and curved, and its vertebrae are remarkable for the position of the canal for the transmission of the vertebral artery, which does not perforate the transverse process, but passes obliquely through the anterior part of the pedicle of the arch.
In the upper jaw there is a compressed, sharp-pointed, tusk-like incisor near the hind edge of the premaxilla, followed in the male at least by a moderate-sized, pointed, curved canine in the anterior part of the maxilla.
Next to the latter is a curved, sub-erect canine, followed after an interval by an isolated minute and often deciduous simple conical premolar; then a contiguous series of one premolar and three molars, which differ from those of recent species of Camelus in having a small accessory column at the anterior outer edge.
In both jaws the anterior front-teeth were of a cutting and compressed type.
In Ireland, Sir William Wilde has assigned their range approximately to the period between the 9th and 16th centuries; while Dr Munro holds that the vast majority of them, both in Ireland and in Scotland, were not only inhabited, but constructed during the Iron Age, and that their period of greatest development was as far posterior to Roman civilization as that of the Swiss Pfahlbauten was anterior to it.
The position of Sceldwea and Beaw (in Malmesbury's Latin called Sceldius and Beowius) in the genealogy as anterior to Woden would not of itself prove that they belong to divine mythology and not to heroic legend.
The use of that dialect (instead of Aeolic) by the Boeotian poet Hesiod, in a kind of poetry which was not of the Homeric type, tends to the conclusion that the literary ascendancy of the epic dialect was anterior to the Iliad and Odyssey, and independent of the influence exercised by these poems.
In the earlier part of his Meletemata (1830) he took up the question of written or unwritten literature, on which Wolf's whole argument turned, and showed that the art of writing must be anterior to Peisistratus.
Most of these, however, fail to afford any useful points of comparison, either from their utter unlikeness to Homer, or because there is no evidence of the existence of anterior popular songs.
The ordinal name for the genera and species of Amphioxus is Cephalochorda, the term referring to the extension of the primary backbone or notochord to the anterior extremity of the body; the family name is Branchiostomidae.
The back of the body is occupied by a crest, called the dorsal fin, consisting of a hollow ridge, the cavity of which is divided into about 250 compartments or fin chambers, into each of which, with the exception of those near the anterior and posterior end of the body, projects a stout pillar composed of characteristic laminar tissue, the fin ray.
It is still longer before the neural tube completes its closure in front, exhibiting a small orifice at the surface, the anterior neuropore.
Indeed, during the last generation, this proportion has been in most cases slightly increased, in consequence of the fall of the birth-rate which set in anterior to this period.
Taken in combination with Machiavelli's treatises, the Opere inedite furnish a comprehensive body of Italian political philosophy anterior to the date of Fra Paolo Sarpi.
The anterior opening of the brain-case is surrounded by a ring of hard cirri.
Anterior to Kant the gradual advance of idealism had been the most conspicuous feature in philo sophic speculation.
He knows that both animals and men have come into existence within assignable limits of time, and that there was an anterior age when no eye or ear gathered the life of the universe into perceptions.
The valves of the shell are closed by a single large adductor muscle, the anterior adductor being absent.
The organization of the oyster, as compared with that of a typical lamellibranch such as Anodon, is brought about by the reduction of the anterior part of the body accompanying the loss of the anterior adductor, and the enlargement of the posterior region.
The heart and pericardial chamber in the oyster lie along the anterior face of the adductor muscle, almost perpendicular to the direction of the gills, with which in Anodon they are parallel.
In this state of equilibrium the great powers of Anterior Asia remained during the first half of the 6th century.
The first two premolars are compressed, with cutting longitudinal edges, the anterior one is deciduous, being lost about the time the second one replaces the milk-molar, so that three premolars are never found in place and use in the same individual.
The molars are usually not longer (from before backwards) than the anterior premolars, and less compressed than in the next section.
The anterior premolar has been shed.
Already by the end of the 12th century the lyric poetry of the troubadours had found cultivators in Portugal, and a few compositions which have come down to us bear a date slightly anterior to the year 1200.
There exists a mid14th-century Historia do Santo Graal, and an unprinted Josep' ab Aramadia, while, though the MS. is lost, we have abundant evidence of the existence of a primitive Portuguese prose redaction of Amadis de Gaula anterior to the present Spanish text.
Berthelot was not prepared to assert that these treatises were actually written by Jaber, but he held it certain that they are works written in Arabic between the 9th and 12th centuries, at a period anterior to the relations of the Latins with the Arabs.
At present we say of such a substance as thebaine, " it acts on the anterior cornua of grey matter in the spinal cord," but why on them and not elsewhere we do not know.
The fresh-water Mussels, Anodonta cygnea, Unio pictorum, and Unio margaritiferus belong to the order Eulamellibranchia of Lamellibranch Molluscs, in which the anterior and posterior adductor muscles are equally developed.
A remarkable feature found only in the Stomatopoda is the reappearance of segmentation in the anterior part of the cephalic region.
In the Phyllopoda they are for the most part all alike, though one or two of the anterior pairs may be specialized as sensory (Apus) or grasping (Estheriidae) organs.
In the thoracic series it is usual for one or more of the anterior pairs to be pressed into the service of the mouth, forming " foot-jaws " or maxillipeds.
In almost all Crustacea the food-canal runs straight through the body, except at its anterior end, where it curves downwards to the ventrally-placed mouth.
In most Decapods the " stomach " or dilated portion of the fore-gut is divided into two chambers, a large anterior " cardiac " and a smaller posterior " pyloric."
The right and left margins of the mantle are united ventrally, leaving an anterior and posterior aperture to the mantle cavity.
The edge of the mantle at the anterior aperture is very thick and muscular; at the posterior aperture also there is a circular muscle, and here the edge is interrupted by a ventral sinus and is provided internally with a dorsal and ventral valve which can be applied to each other so as to close the aperture.
The captacula are tactile and prehensile and can be protruded from the anterior aperture of the mantle.
The foot is elongated and cylindrical, and can be protruded from the anterior aperture to serve as a burrowing organ.
The renal organs are a pair of short wide sacs with folded walls lying on either side of the anterior end of the liver.
The gonad, whose position has already been mentioned, is divided into transverse lobes; its duct is anterior and single, and diverges to the right to open into the right kidney as in primitive Gastropods and Lamellibranchs.
Fringe surrounding the anterior opening of the mantle-chamber.
The head is situated on the dorsal side of the body anteriorly within the anterior aperture of the mantle, from which it cannot be protruded.
It is a small somewhat cylindrical projection with the mouth at its anterior end.
The gastrula thus formed has a large blastopore, which is at first posterior but afterwards gradually moves towards the anterior end of the ventral surface.
Shell curved with greatest diameter at anterior aperture and diminishing gradually to posterior.
Foot expanded distally into a symmetrical disk with a crenate edge or simple and vermiform without well-developed lateral processes; shell often contracted towards the anterior aperture.
The neurae are arranged at the axis of the wing after the manner of a fan or spiral stair - the anterior one occupying a higher position than that farther back, and so of the others.
The posterior margin of the wing is made to rotate, during the down stroke, in a direction from above downwards and from behind forwards - the anterior margin travelling in an opposite direction and reciprocating.
The wing of the bird, like that of the insect, is concavo-convex, and more or less twisted upon itself when extended, so that the anterior or thick margin of the pinion presents a different degree of curvature to that of the posterior or thin margin.
The twisting referred to is partly a vital and partly a mechanical act; - that is, it is occasioned in part by the action of the muscles and in part by the greater resistance experienced from the air by the tip and posterior margin of the wing as compared with the root and anterior margin, - the resistance experienced by the tip and posterior margin causing them to reverse always subsequently to the root and anterior margin, which has the effect of throwing the anterior and posterior margins of the wing into figure-of-8 curves, as shown at figs.
The flexibility and elasticity of the kite formed by the natural wing are rendered necessary by the fact that the wing, as already stated, is practically hinged at its root and along its anterior margin, an arrangement which necessitates its several parts travelling at different degrees of speed, in proportion as they are removed from the axes of rotation.
If the anterior margins of natural and artificial wings were rigid, it would be impossible to make them vibrate smoothly and continuously.
If a rigid rod, or a wing with a rigid anterior margin, be made to vibrate, the vibration is characterized by an unequal jerky motion, at the end of the down and up strokes, which contrasts strangely with the smooth, steady fanning movement peculiar to natural wings.
He describes two artificial wings, the one composed of a rigid rod and sail - the rod representing the stiff anterior margin of the wing; the sail, which is made of paper bordered with cardboard, the flexible posterior margin.
On the anterior margin the extended nervures make it rigid, while behind it is fine and flexible.
It is of a more or less triangular form, thick at the root and anterior margin, and thin at the tip and posterior margin.
The tip and posterior parts of the wing are more active than the root and anterior parts, from the fact that the tip and posterior parts (the wing is an eccentric) always travel through greater spaces, in a given time, than the root and anterior parts.
Wind up the string by turning the flyers different ways, so that the spring of the bow may unwind them with their anterior edges ascending; then place the cork with the bow attached to it upon a table, and with a finger on the upper cork press strong enough to prevent the string from unwinding, and, taking it away suddenly, the instrument will rise to the ceiling."
The cardinal idea was to force the aeroplanes (slightly elevated at their anterior margins) forwards, kite-fashion, by means of powerful vertical screw propellers driven at high speed - the greater the horizontal speed provided by the propellers, the greater, by implication, the lifting capacity of the aerodrome.
The machine was furnished with two wheels and vertical supports which depended from the anterior parts of the aeroplanes and supported it when it touched the ground FIG.
In the vast majority there are three stamens alternating with the lodicules, and therefore one anterior, i.e.
Many of the bamboos have a third, anterior, style.
There is a sheet at the Louvre of much earlier date than the first idea or commission for this particular picture, containing some nude sketches for the arrangement of the subject; another later and farther advanced, but still probably anterior to the practical commission, at Venice, and a MS. sheet of great interest at the Victoria and Albert Museum, on which the painter has noted in writing the dramatic motives appropriate to the several disciples.
The facial portion of the skull is very short; a long process of the maxillary bone descends from the anterior part of the zygomatic arch; and the ascending ramus of the mandible is remarkably high.
The single blowhole is a longitudinal slit, placed at the upper and anterior extremity of the head to the left side of the middle line.
The anterior wings, when present, are always small; but the posterior wings are sometimes of large size and very beautifully coloured.
Lastly, he showed, both from theoretical considerations and from the result of actual experiment on the living animal, that the anterior roots of the spinal nerves are motor, while the posterior are sensory.
To render the organization of this creature perfect in relation to its wants, it is provided with three long filaments inserted along the middle of the head, which are, in fact, the detached and modified three first spines of the anterior dorsal fin.
The beak is large, strong and sharp-edged, the upper mandible terminating in a large hook; the wings are narrow and very long; the feet have no hind toe, and the three anterior toes are completely webbed.
There was probably a nervous area, with a tuft of cilia, at the anterior end; while, at all events in forms that remained pelagic, the ciliated nervous tracts of the rest of the body may be supposed to have become arranged in bands around the body-segments.
The middle cavities were smaller, and the ducts from them came to unite with those from the anterior cavities, and no longer opened directly to the exterior; whether these cavities were already specialized as water-sacs cannot be asserted, but they certainly had become so at a slightly later stage.
The forward portion of the anterior coelom shared in the constriction and elongation of the preoral lobe; but its hinder portion was dragged up along with the water-pore and formed a canal lying moccth ive along the outer wall (the gerei tatpore parietal canal).
Since this must have, on our theory, enclosed the parietal canal from the anterior coelom, it is possible that the genital products were developed from the lining cells of that cavity, and that the genital pore was nothing but its original pore not yet united with that from the water-sac. The concrescence of these pores can be traced in other cystids; but as the genital organs became affected by radial symmetry the original function of the duct was lost, and the reproductive elements escaped to the exterior in another way.
The remains of the original genital gland within the theca became the "axial organ" surrounded by the "axial sinus" derived from the anterior coelom, and this again by structures derived from the right posterior coelom, which, as explained above, had been depressed to the aboral pole.
It is thus demonstrable that the material for our Grail legend, in its present form, existed long anterior to any extant text, and there is no improbability in holding that a confused tradition of pagan mysteries which had assumed the form of a popular folk-tale, became finally Christianized by combination with an equally popular ecclesiastical legend, the point of contact being the vessel of the common ritual feast.
In the Argasidae the anterior portion of the dorsal surface of the body is extended forwards above the capitulum, so that this structure is concealed from above; the integument is fairly uniformly granular or coriaceous above and below; the palpi are simple and unmodified; there is no sucker beneath the claws in the adult, and there is only a slight structural difference between the sexes.
In the Ixodidae the capitulum is not overlapped by a forward extension of the dorsal area, which is smooth and firmly chitinized either in front or all over; the palpi are usually modified, that is to say, their second and third segments are usually excavated internally to form a sheath for the hypostome; there is a distinct sucker beneath the claws and the difference between the sexes is well marked, the males having the dorsal integument thickly and continuously chitinized, whereas in the females only its anterior portion bears a chitinous plate, the rest of the integument being soft to admit of its distension by the blood which is imbibed in quantity by members of this sex.
Those of each jaw are placed in continuous series without intervals between them; and, although the anterior teeth are simple and single-rooted, and the posterior teeth complex and with several roots, the transition between the two kinds is gradual.
The eight remaining teeth of the upper jaw offer a natural division, inasmuch as the three hindmost never have milk-predecessors; and, although some of the anterior teeth may be in the same case, the particular one preceding these three always has such a predecessor.
Of the five teeth between the incisors and molars the most anterior, or the one usually situated close behind the premaxillary suture, very generally assumes a lengthened and pointed form, and constitutes the " canine " of the Carnivora, the tusk of the boar, &c. It is customary, therefore, to call this tooth, whatever its size or form, the " canine."
The anterior part of the palate is composed of mucous membrane tightly stretched over the flat or slightly concave bony layer which separates the mouth from the nasal passages, and is generally raised into a series of transverse ridges, which sometimes, as in ruminants, attain a considerable development.
Its food consists mainly of termites, to obtain which it opens their nests with its powerful sharp anterior claws, and as the insects swarm to the damaged part of their dwelling, it draws them into its mouth by means of its long, flexible, rapidly moving tongue covered with glutinous saliva.
Though generally an inoffensive animal, when attacked it can defend itself vigorously and effectively with its sabre-like anterior claws.
One portion of the Aryans emigrated and settled in what is now Wakhhan (on the Pamir plateau), the present language of which seems very old, dating anterior to the separation of the Vedic and Zend languages.
The antheridia are deeply sunk in the tissue; the spermatozoids consist of a spiral of two or three coils, the numerous cilia being attached to the pointed anterior end.
The eyes in some Crustacea are mounted on articulated stalks, and from the fact that they can after injury be replaced by antennalike appendages it is inferred that they represent the parapodia of the most anterior prosthomere.
Indeed Locke seems to allow that the consent was at first tacit, and by anterior law of nature conditional on the beneficial purpose of the trust being realized.
The form of the ear depends on the relative width of the anterior and posterior surfaces as compared with that of the lateral surfaces.
From this the blood passes into two lateral vessels which pierce the coelomic septum (s.), the right vessel proceeding on the anterior side of the oesophagus, as shown in fig.
It is possible that this consideration will account for the want of an anterior body-cavity in Phoronis.
His theory of the state, despite Grotius and Jurieu, rejected as odious and even impious the notion of any popular rights, anterior and superior to his own.
The origin of the three main divisions of Lincolnshire is anterior to that of the county itself, and the outcome of purely natural conditions, Lindsey being in Roman times practically an island bounded by the swamps of the Trent and the Witham on the west and south and on the east by the North Sea, while Kesteven and Holland were respectively the regions of forest and of fen.
Upon hatching, the young, which differ from the adult in possessing long antennae and a pair of powerful fossorial anterior legs, fall to the ground, burrow below the surface, and spend a prolonged subterranean larval existence feeding upon the roots of vegetation.
All the rays through a given point in the first principal focal plane of the anterior system of lenses traverse the plate as a parallel beam and reunite at the corresponding point of the second focal plane of the posterior system, each in its passage being divided into two by the plate having a given relative retardation.
The mouth is anterior and slightly ventral; it leads into a protrusible pharynx armed with recurved teeth that can be everted.
The opening of the anterior nostrils is prolonged backwards on each side of the face between the nasals and the elongated slender premaxillae.
The palate is narrow in the interval between the incisor and molar teeth, in which are situated the large anterior palatine foramina.
It completely embraces the truncated cylindrical tympanohyal, which is of great size, corresponding with the large development of the whole anterior arch of the hyoid.
The basi-hyal is remarkable for the long, median, pointed, compressed " glossohyal " process, which it sends forward from its anterior border into the base of the tongue.
The spinous processes of the anterior thoracic region are high and compressed.
The sternum consists of six pieces; the anterior or presternum is compressed and projects forwards like the prow of a boat.
The anterior premolars are quite rudimentary, sometimes not developed at all, and generally fall by the time the animal attains maturity, so that there are but six functional cheek teeth, - three that have predecessors in the milk-dentition, and hence are considered as premolars, and three molars, but otherwise, except the first and last of the series, not distinguishable in form or structure.
It consists of a compressed intermolar portion with a flat upper surface, broad behind and becoming narrower in front, and of a depressed anterior part rather shorter than the former, which is narrow behind and widens towards the evenly rounded apex.
Its duct leaves the inferior anterior angle, at first descends a little, and runs forward under cover of the rounded inferior border of the lower jaw, then curves up along the anterior margin of the masseter muscle, becoming superficial, pierces the buccinator, and enters the mouth by a simple aperture opposite the middle of the crown of the third premolar tooth.
Its posterior end rests against the anterior surface of the transverse process of the atlas, from which it extends forwards and downwards, slightly curved, to beneath the ramus of the jaw.
There is one anterior vena cava, formed by the union of the two jugular and two axillary veins.
The aorta gives off a large branch (the anterior aorta) very near its origin, from which arise - first, the left axillary, and afterwards the right axillary and the two carotid arteries.
The central nervous system, the anterior part of which is shown in fig.
A and feet with two primary papillae on the anterior side and one on the posterior side; outer jaw with one minor tooth at the base of the main tooth, inner jaw with no interval between the large tooth and the series of small ones; last fully developed leg of the male with enlarged crural gland opening on a large papilla placed on its ventral surface; coxal organs absent; the nephridial openings of the 4th and 5th pairs of legs are placed in the proximal spinous pad.
A variable number of posterior legs of the males anterior to the genital opening with one or two large papillae carrying the openings of the crural glands; well-developed coxal organs present on most of the legs.
With 23 to 25 pairs of claw-bearing legs, four spinous pads on the legs, and nephridial openings of legs 4 and 5 in the middle of the proximal pad or on its proximal side; feet with two primary papillae, one anterior and one posterior; outer jaw with two, inner jaw with two or three minor teeth at the base of the main tooth, separated by a diastema from the row of small teeth; crural glands present in the male only, in the two pairs of legs preceding the generative opening; coxal glands present.
To determine the position of the anterior focal plane of the eyepiece, the eyepiece is placed on the stage with the eye-lens downwards.
This gives the distance of the anterior focal plane of the eyepiece from the bottom edge of the setting of the eyepiece and consequently also of the edge of the eyepiece carried by the upper end of the tube.
In the order Scrophulariaceae one of the two carpels is posterior and the other anterior, whilst in Convolvulaceae the carpels are arranged laterally.
The upper lip is often composed of three parts, which are thus posterior