Tentacles sentence example
The daughter-individuals grow, form the full number of twenty-four tentacles and divide again.
Was there any place far enough away to escape the tentacles of paternal love?
The sub-umbrella invariably shows a velum as an inwardly projecting ridge or rim at its margin, within the circle .of tentacles; hence the medusae of this sub-class are termed craspedote.
The nematocysts of the ectoderm may be grouped to form batteries on the tentacles, umbrellar margin and oral lappets.
Protohydra is a marine genus characterized by the absence of tentacles, by a great similarity to Hydra in histological structure, and by reproduction by transverse fission.Advertisement
A " stolon " of unknown origin produces thirty-two buds, which become as many Polypodia; each has twenty-four tentacles and divides by fission repeated twice into four individuals, each with six tentacles.
The float is covered with long tentacles and bears the medusa-buds.
Arms, tentacles, and antennae stretched for it.
As regards number, we find in the aberrant forms Protohydra and Microhydra tentacles entirely absent.
Finally, as regards structure,S the tentacles may retain their primitive hollow nature, or become solid by obliteration of the axial cavity.Advertisement
Head bears two pairs of tentacles.
Ampullaria has very long tentacles and a long siphon formed by the mantle.
It has to be a Seafood Special with extra octopus tentacles.
The polyps arefree and walk on their tentacles.
Ocelli are seen at the base of the tentacles, and also (as an exception) groups of medusiform buds.Advertisement
Club-shaped hydranths with numerous tentacles, generally scattered irregularly, sometimes with a spiral arrangement, or in whorls (" verticillate ").
The tentacles may be scattered singly round the margin of the umbrella (" monerenematous ") or arranged in tufts (" lophonematous "); in form they may be simple or branched (Cladonemid type); in structure they may be hollow (" coelomerinthous "); or solid (" pycnomerinthous ").
Trophosome, polyps with two whorls of tentacles, the lower filiform, the upper capitate; gonosome, free medusae, with tentacles solid and branched.
Trophosome, polyps with a single whorl of capitate tentacles; gonosome, free medusae, with ten tacles branched, solid.
Corymorphidae (including the medusa-family Hybocodonidae).--, Trophosome solitary polyps, with two whorls of tentacles; gonosome, free medusae or gonophores.Advertisement
The genus Myriothela is a solitary polyp with scattered capitate tentacles, producing sporosacs.
Trophosome (only known in one genus), polyps with two tentacles forming a creeping colony; gonosome, free medusae with four, six or more radial canals, giving off one or more lateral branches which run to the margin of the umbrella, with the stomach produced into four, six or more lobes, upon which the gonads are developed; the mouth with four lips or with a folded margin; the tentacles simple, arranged evenly round the margin of the umbrella.
The proboscis bears at its extremity a circlet of smaller oral tentacles.
The medusae, on the other hand, have the tentacles in four tufts of (in the buds) five each, and thus resemble the medusae of the family Margelidae.
The hydranth almost always has a single circlet of tentacles, like the Bougainvillea-type in the preceding sub-order; an exception is the curious genus Clathrozoon, in which the hydranth has a single tentacle.Advertisement
The medusa-buds, as already stated, are always produced from blastostyles, reduced non-nutritive polyps without mouth or tentacles.
A-D are stages common to both; from D arises the hydrotheca (E) or the gonotheca (F); th, theca; st, stomach; 1, tentacles; m, mouth; mb, medusa-buds.
The tentacles are usually hollow, rarely solid (Obelia) .
Primitively there are four perradial tentacles, to which may be added four interradial, or they may become very numerous and are then scattered evenly round the margin, never arranged in tufts or clusters.
In addition to tentacles, there may be marginal cirri (Laodice) with a solid endodermal axis, spirally coiled, very contractile, and bearing a terminal battery of nematocysts.
The manubrium bearing the gonads is mouthless, and the umbrella is without tentacles, sense-organs, velum or radial canals.
The dactylozoids have no mouth; in Milleporidae they have short capitate tentacles, but lack tentacles in Stylasteridae.
Medusae with sense-organs represented by otocysts derived from modified tentacles (tentaculocysts), containing otoliths of endodermal origin, and innervated from the ex-umbral nerve-ring.
Prolongations from the rim of chondral tissue may form clasps or peronia supporting the tentacles.
The tentacles are always solid, containing an axis of endoderm-cells resembling notochordal tissue or plantparenchyma, and are but moderately flexible.
Other genera are Aglauropsis, Gossea and Gonionemus; the last named bears adhesive suckers on the tentacles.
Eight radial canals, two, four or eight gonads; tentacles numerous; tentaculocysts free; stomach prolonged into manubrium.
Eight very broad radial canals; ex-umbrella often provided with lateral outgrowths; tentacles differing in size, but in a single row.
The tentacles are not inserted on the margin of the umbrella, but arise high up on the ex-umbral surface, and the umbrella is prolonged into lobes corresponding to the interspaces between the tentacles.
The condition of things can be imagined by supposing that in a medusa primitively of normal build, with tentacles at the margin, the umbrella has grown down past the insertion of the tentacles.
The radial canals are represented by wide gastric pouches, and may be absent, so that the tentacles arise directly from the stomach (Solmaridae).
The tentacles are always solid, as in Trachomedusae.
The two ends of the planula become greatly lengthened and give rise to the two primary tentacles of the actinula, of which the mouth arises from one side of the planula.
No gastric pouches; the numerous tentacles arise direct from the stomach, into which also the peronial canals open, so that the ring-canal is cut up into separate festoons.
In both cases the hydranth is extremely reduced and has no tentacles, and the polyp forms a colony by budding from the base.
As yet, however, the medusa of Microhydra has only been seen in an immature condition, but it shows some well-marked differences from Limnocodium, especially in the structure of the tentacles, which furnish useful characters for distinguishing species amongst medusae.
The tentacles of siphonophores may reach a great length and have a complex structure.
Droscra, another of this insectivorous group, has leaves which are furnished with long glandular tentacles.
More slowly, but yet in the same way, we may note the change in turgidity of certain cells of the Droscra tentacles, as they close over the imprisoned insect.
These occur on the tips of tendrils and on the tentacles of Drosera; (2) sensitive papillae found on the irritable filaments of certain stamens; and (3) sensitive hairs or bristles on the leaves of Dionaea muscipula and Mimosa pudicaall of which are so constructed that any pressure exerted on them at once reacts on the protoplasm.
The head bears only one pair of tentacles.
Stomatella, foot truncated posteriorly, an oper culum present, no epipodial tentacles.
Shell spirally coiled; epipodial tentacles present; operculum thick and calcareous.
The head is seen in front resting on the foot and carrying a median non-retractile snout or rostrum, and a pair of cephalic tentacles at the base of each of which is an eye.
Shell flattened; no cephalic tentacles.
Shell spiral; four cephalic tentacles; eyes absent; two pedal appendages.
Animal fixed by the shell, the last whorls of which are not in contact with each other; foot small; two anterior pedal tentacles.
Shell thin; operculum absent; tentacles bifid; foot secretes a float; pelagic. Janthina.
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.
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 oval, covering the head and the greater part of the body; anterior tentacles,.
Never more than one pair of tentacles, and these are absent in Alderia and some species of Limapontia.
Body elongated, with lateral expansions; tentacles large; foot narrow.
In both Oncidiidae and Pecten the pallial eyes have probably been developed by the modification of tentacles, such as coexist in an unmodified form with the eyes.
The head bears a single pair of contractile but not invaginable tentacles, at the base of which are the eyes.
Shell spirally coiled; head broad, without prominent tentacles; foot short, operculated; marine.
Visceral mass and shell conical; tentacles atrophied; head expanded; genital apertures contiguous; marine animals, with an aquatic pallial cavity containing secondary branchial laminae.
Pulmonata with two pairs of tentacles, except Janellidae and Vertigo; these tentacles are invaginable, and the eyes are borne on the summits of the posterior pair.
Anterior tentacles much reduced; male and female apertures contiguous but distinct; shell thin,.
They are cylindrical worm-like animals, with a median anterior mouth quite devoid of any armature or tentacles.
The head is produced into ciliated arms bearing tentacles.
Anteriorly this base supports a gurrie or gutter, the pre-oral rim of which is formed by a simple lip, but the post-oral rim is composed of a closely set row of tentacles.
Externally on two sides and on the inner surface the tentacles are ciliated, and the cilia are continued across the 5 gutter to the lip and even on the outer surface of the latter.
In Terebratulina, Rhyn- chonella, Lingula, and possibly other genera, the arms can be unrolled and protruded from the opened shell; in this case the tentacles also FIG.
The great arm-sinus of each side of the lophophore lies beneath the fold or lip which together with the tentacles forms the ciliated groove in which the mouth opens.
The small arm-sinus runs along the arms of the lophophore at the base of the tentacles, and gives off a blind diverticulum into each of these.
The cirri or tentacles, of which three or four pairs are present, are capable of being protruded, and the minute larva swims by means of the ciliary action they produce.
It can retract the tentacles, shut its shell, and sink to the bottom.
In one genus (Polypocephalus) the place of a rostellum is taken by a crown of retractile tentacles.
Another form, Rhopalophorus, has two cephalic tentacles that are retractile and covered with hooks.
They may be defined as aquatic animals, forming colonies by budding; with ciliated retractile tentacles and a U-shaped alimentary canal.
Tentacles infolded, during retraction, into a vestibule which can.
Tentacles retractile into an introvert ("tentacle-sheath").
The tentacles are expanded in some of the latter.
In Loxosoma panded tentacles.
The polypide consists of a "lophophore" bearing a series of ciliated tentacles by which Diatoms and other microscopic bodies are collected as food, of a U-shaped alimentary canal, and of a central nervous system.
The lophophore is a simple circle in all Polyzoa except in the Phylactolaemata, where it typically has the form of a horse shoe outlined by the bases of the tentacles.
The cavities of the hollow tentacles open into a circular canal which surrounds the oesophagus at the base of the lophophore.
In the Entoprocta the tentacles are withdrawn by being infolded into the "vestibule," a depression of the oral surface which can be closed by a sphincter muscle.
In some Gymnolaemata, polypides which develop an ovary possess a flask-shaped "intertentacular organ," situated between two of the tentacles, and affording a direct passage into the introvert for the eggs or even the spermatozoa developed in the same zooecium.
The exchange of fluid in the sac may well have a respiratory significance, in addition to its object of facilitating the movements of the tentacles.
It can hardly be doubted that the function of these avicularia is the protection of the tentacles and compensation-sac. The suggestion that they are concerned in feeding does not rest on any definite evidence, and is probably erroneous.
The vestibule breaks through to the exterior, and the tentacles, which have been developed within it, are brought into relation with the external water.
Herpeton of Cambodia has a pair of long tentacles on the snout and is said to have a partly vegetable diet!
In this way is formed a ring of tentacles, the most characteristic organs of the Cnidaria.
Thus the body becomes umbrellashaped, the concave side representing the peristome, and the convex side the column, of the polyp. Hence the tentacles are found at the edge of the umbrella, and the hypostome forms usually a projecting tube, with the mouth at the extremity, forming the manubrium or handle of the umbrella.
The medusa has a pronounced radial symmetry, and the positions of the primary tentacles, usually four in number, mark out the so-called radii, alternating with which are four interradii.
The name medusa is suggested by the tentacles, usually long and often numerous, implanted on the edge of the umbrella and bear the stinging organs of which sea-bathers are often disagreeably aware.
The tentacles serve for the capture of prey and are very contractile, being often protruded to a great length or, on the other hand, retracted and forming corkscrew-like curls.
The umbrella-like body bears a circle of tentacles at the edge, whereby the body can be divided into a convex exumbrella or exumbral surface and a concave subumbrella or subumbral surface.
In addition to the tentacles, the margin of the umbrella bears sense-organs, which may be of several kinds and may attain a high degree of complexity.
Medusae capture their prey, consisting of small organisms of various kinds, especially Crustacea, by means of the tentacles which hang out like fishing-lines in all directions.
When the prey comes into contact with the tentacles it is paralysed, and at the same time held firmly, by the barbed threads shot out from the stinging organs or nematocysts.
Then by contraction of the tentacles the prey is drawn into the mouth.
The exumbral nerve-ring is the larger and supplies the tentacles; the subumbral ring supplies the velum.
The marginal tentacles may be very numerous or may be few in number or even absent altogether; and they may be simple filaments, or branched in a complicated manner.
The oral arms are the starting-point of a further series of variations; they may be simple flaps, crinkled and folded in various ways, or they may be subdivided, and then the branches may simulate tentacles in appearance.
The sense-organs are always situated at the margin of the unbrella and may be distinguished from the morphological point of view into two categories, according as they are, or are not, derived from modifications of tentacles; in the former case they are termed tentaculocysts.
The crown of tentacles thus comes to form a fringe to the margin of the body, and the hypostome becomes the manubrium.
A medusa with a remarkable habit of life is Mnestra parasites, which is parasitic on the pelagic mollusc Phyllirrhoe, attaching itself to the host by its subumbral surface; its tentacles, no longer required for obtaining food, have become rudimentary.
In some Lamellibranchs (Pecten, Spondylus, Pholas, Mactra, Tellina, Pectunculus, Galeomma, &c.), although cephalic eyes are generally absent, special eyes are developed on the free margin of the mantle-skirt, apparently by the modification of tentacles commonly found there.
In such Lamellibranchs as the oysters, scallops and many others which have the edges of the mantleskirt quite free, there are numerous tentacles upon those edges.
We thus expose the plough-like foot (I), the two left labial tentacles, and the two left gill-plates or left ctenidium.
The gill-plates have a structure very different from that of the labial tentacles, and one which in Anodonta is singularly complicated as compared with the condition presented by these organs in some other Lamellibranchs, and with what must have been their original condition in the ancestors of the whole series of living Lamellibranchia.
Anodonta has no eyes of any sort, and the tentacles on the mantle edge are limited to its posterior border.
This deficiency is very usual in the class; at the same time, many Lamellibranchs have tentacles on the edge of the mantle supplied by a pair of large well-developed nerves, which are given off from the cerebro-pleural ganglion-pair, A, When free swimming, shows the two dentigerous valves widely open.
They have originated not as pits but as tentacles.
The labial tentacles are formed late.
The two branched tentacles (TB) are seen partially extruded from their sheaths (TS); when fully extended they exceed the diameter of the animal five or six times.
The short tentacles (T) are drawn on one side only.
The early larval stage of the " Lobster Moth " (Stauropus fagi), for example, presents a general resemblance, due to a combination of shape, colour, attitude and movements, to black ants, the swollen head and the caudal disk with its two tentacles representing respectively the abdomen and antenna-bearing head of the model.
The body is composed of a large number of segments; the prostomium bears a pair of tentacles; the nervous system consists of a brain and longitudinal ventral nerve cords closely connected with the epidermis (without distinct ganglia), widely separated in Saccocirrus, closely approximated in Protodrilus, fused together in Polygordius; the coelom is well developed, the septa are distinct, and the dorsal and ventral longitudinal mesenteries are complete; the nephridia are simple, and open into the coelom.
In Phascolosoma and Phascolion this funnelshaped structure has broken up into a more or less definite group of tentacles, which in Dendrostoma are arranged in four groups.
In Aspidosiphon and Physcosoma the tentacles are usually arranged in a horse-shoe, which may be double, overhanging the mouth dorsally.
On the surface of the funnel-shaped lophophore are numerous ciliated grooves, and each of the tentacles in the tentaculated forms has a similar groove directed towards the mouth.
A so-called heart lies on the dorsal surface of the oesophagus; it is closed behind, but in front it opens into a circumoesophageal ring, which gives off vessels into the lophophore and tentacles.
The contraction of this heart, which is not rhythmic, brings about the expansion of the tentacles and lophophore.
It is simply a hydrostatic mechanism for expanding the tentacles.
The velum is also provided with a circlet of twelve tantacles (in some species sixteen) which hang backwards into the pharynx; these are the velar tentacles.
The sense-organs are covered over by flaps of the umbrellar margin (hence " Steganophthalmata "), and are always tentaculocysts, that is to say, reduced and modified tentacles, which bear usually both ocelli and otocysts, and are hollow.
Such forms when undisturbed fix themselves to the bottom and rest with their mouths and tentacles uppermost.
The tentacles vary in number from four, the primitive I.
From the edges of the vase the four primary tentacles grow out, each a slender filament with a solid endodermal axis.
The tentacles border a broad, flattened peristome, from the centre of which arises the hypostome with the mouth at its extremity; the hypostome is at first low, but soon becomes a projecting, chimney-like tube.
The single ephyra carries the sixteen scyphistoma tentacles, which will atrophy and disappear.
The sixteen tentacles of the scyphistoma disappear, and in the place of the four perradial and four interradial tentacles, the eight tentaculocysts of the adult are formed as outgrowths of the subumbral margin, independently of the tentacles of the scyphistoma (Friedemann).
Sessile, stalked, with eight shallow marginal lobes bearing one or more rows of tentacles; without tentaculocysts; with four gonads.
Sessile, with the margin undivided; with eight colletocystophores and eight adradial groups of capitate tentacles.
With sixteen marginal lobes, four rhopalia and twelve tentacles; the rhopalia are perradial in position, corresponding to the angles of the stomach.
Above to left, young scyphistoma with four perradial tentacles.
Below to left, scyphistoma with sixteen tentacles and first constriction.
To the right, strobila condition of the scyphistoma, consisting of thirteen metameric segments; the uppermost still possesses the sixteen tentacles of the scyphistoma; the remainder have no tentacles, but are ephyrae, each with eight bifid arms (processes of the disc).
Each tentacle is to the stem of a plant, and is repre sented with the base of attachment a glove-finger like outpush uppermost; the mouth, not actually ing of the whole wall of the seen in the drawing, is at the lower sac and contains typically extremity of the body, surrounded a prolongation of its internal by the circle of tentacles.
The tentacles are organs which serve both for the tactile sense and for the capture of food.
By means of the stinging nettle-cells or nematocysts with which the tentacles are thickly covered, living organisms of various kinds are firmly held and at the same time paralysed or killed, and by means of longitudinal muscular fibrils formed from the cells of the ectoderm the tentacles are contracted and convey the food to the mouth.
By means of circularly disposed muscular fibrils formed from the endoderm the tentacles can be protracted or thrust out after contraction.
We can distinguish therefore in the body of a polyp the column, circular or oval in section, forming the trunk, resting on a base or foot and surmounted by the crown of tentacles, which enclose an area termed the peristome, in the centre of which again is the mouth.
As a rule there is no other opening to the body except the mouth, but in some cases excretory pores are known to occur in the foot, and pores may occur at the tips of the tentacles.
The tentacles may number many hundreds or may be very few, in rare cases only one or two, or even absent altogether; they may be long and filamentous, or short and reduced to mere knobs or warts; they may be simple and unbranched, or they may be feathery in pattern.
The individual animal or zooid of Actinia equina has the form of a column fixed by one extremity, called the base, to a rock or other object, and bearing at the opposite extremity a crown of tentacles.
The tentacles surround an area known as the peristome, in the middle of which there is an elongated mouth-opening surrounded by tumid lips.
In common with all Coelenterate animals, the walls of the columnar body and also the tentacles and peristome of Actinia are composed of three layers of tissue.
The lastnamed are specially numerous on the tentacles and on some other regions of the body, and produce the well-known "thread cells," or nematocysts, so characteristic of the Coe lentera.
There are always eight tentacles, which are hollow and fringed on their sides, with hollow projections or pinnae; and always eight mesenteries, all of which are complete, i.e.
In these the tentacles are stunted or suppressed and the mesenteries are ill-developed, but the sulcus is unusually large and has long cilia.
Its body is divisible into three portions, an upper capitulum bearing the mouth and tentacles, a median scapus covered by a friable cuticle, and a terminal physa which is rounded.
There are from sixteen to thirty-two simple tentacles, but only eight mesenteries, all of which are complete.
They have two circlets of tentacles, a labial and a marginal, and there is only one ciliated groove in the stomodaeum, which appears to be the sulculus.
Each zooid has six tentacles; the stomodaeum is elongate, but the sulcus and sulculus are very feebly represented.
Semon called this stage the Pentactula, and supposed that, in its early history, the class had passed through a similar stage, which he called the Pentactaea, and regarded as the ancestor of all Echinoderms. It has since been proved that the five tentacles with their canals are interradial, so that one can scarcely look on the Pentactula as a primitive stage, while the apparent simplicity of the Synaptidae, at least as compared with other holothurians, is now believed to be the result of regressive vlu.
Such a form gave rise to descendants differing inter se as regards the suppression of the radial canals and of the podia, the form of the tentacles, and the development of respiratory trees.
Tentacles supplied from circular canal.
The parapodia of Chaetopoda are never coated with dense chitin, and are, therefore, never converted into jaws; the primitive " head-lobe " or prostomium persists, and frequently carries eyes and sensory tentacles.
In Peripatus the prostomium of the Chaetopod-like ancestor is atrophied, but it is possible that two processes on the front of the head (FP) represent in the embryo the dwindled prostomial tentacles.
The single prosthomere carries the retractile tentacles as its "parapodia."
The appendages of the first prosthomere are not present as tentacles, as in Peripatus and Diplopods, but are possibly represented by the eyes or possibly altogether aborted.
The praeseptal or lophophoral coelom is continued into each of the tentacles and into the (After Allman.) FIG.
Fused bases of the tentacles.
The principal blood-channels are two longitudinal vessels which run down the entire length of the body, and are known as the " afferent " vessel (af) and the " efferent " vessel (ef) respectively, from their relation to the tentacles.
The eggs of Phoronis are small and usually undergo their early development attached to the tentacles of the adult.
The mouth (o) is in front of the tentacles, on the ventral side, and is overhung by a mobile praeoral hood, in which is the principal part of the nervous system.
An oblique septum which follows the bases of the tentacles and corresponds with that of the adult animal divides the body-cavity into two portions.
Most of the praetentacular region and the larval tentacles separate off, being then taken into the alimentary canal, where they are digested.
The long tentacles of the integument may have served to facilitate pollination.
They are colorful, easy to find and never stray far from their ' home ' in the tentacles of their host anemone.
The starter of grilled squid comes with wonderfully crisp tentacles climbing up a vertical wooden skewer.
The most frenzied scrutiny failed to disclose any eldritch tentacles writhing from the graves, nor even a consolatory puddle of blasphemous ichor.
Born in 1863, it has grown into a vast subterranean labyrinth with even vaster tentacles stretching out over the surface of the Earth.
This tuft of tentacles is called the lophophore and can be retracted quickly by a strong muscle fixed into the envelope.
They have a number of different types of stinging cells, called nematocysts, on their tentacles.
It had a milky white bell with a salmon-pink petticoat and frilly white tentacles.
I lost a stirrup, but my legs clung on like tentacles.
Several effects including a fantastic silver strobe effect that leaves long drifting tentacles in this long exposure shot.
The tentacles will feel slightly tacky to the touch.
Shaped roughly like an octopus, the massif extends six tentacles or arms around 12 lakes.
When an insect lands on a sundew, its legs and wings get caught on the sticky tipped tentacles like flies on fly paper.
The veritable Est Est Est chain has tentacles reaching out across the north west.
I looked up, saw tentacles in front of my face.
The mouth is surrounded by tentacles used for the intake of food.
There were quite a thick bunch of stinging tentacles still attached, to a length of about 15 cm.
Suddenly, the pulsing core shot long tentacles through the surrounding rock.
Its a funny looking fish, with many thin tentacles on its face.
Then, flapping out of the doorway, six slimy green tentacles with snake heads emerged, hissing loudly.
With translucent white tentacles, waving like wings in a breeze, they are a wonderful sight to greet the amateur microscopist.
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Sagartia troglodytes with the tentacles retracted underneath a rock, with a drooping goblet appearance.
The tentacles are based on a muscular band called the velum.
The tentacles have stinging cells which they use to capture prey like small water fleas.
The ventral and lateral parts of the anterior margin of the collar constitute the so-called operculum (op.), a structure which not only acts as a lower lip, but must be important in separating the food-current produced by the cilia of the tentacles from the external apertures of the collar-canals and gill-slits.
Thus the arms are reduced to a single pair and possess no tentacles, there is no definite operculum, and the -alimentary canal is vestigial.
As regards form, the tentacles show a.number of types, of which the most important are (I) filiform, i.e.
Radii a multiple of four, with radial gastric pouches bifurcated or subdivided; the tentacles are implanted in the notch between the two subdivisions of each (primary) gastric pouch, hence the (secondary) gastric pouches appear to be " internemal " in position, i.e.
Shell depressed, with rounded aperture; cephalic tentacles long.
Shell fusiform and solid, aperture elongated, columella folded; no operculum; eyes on sides of tentacles.
Shell turriculated, with numerous whorls; aperture and operculum oval; eyes at summits of tentacles; siphon long.
Within the velar area the eyes and the cephalic tentacles commence to rise up, and on the surface of the post-oral region is formed a cap-like shell and an encircling ridge, which gradually increases in prominence and becomes the freely depending mantle-skirt.
Shell with short spire, and wide oval aperture; tentacles short.
It becomes visible when the polypide begins to protrude its tentacles, making its appearance through the orifice as a delicate hyaline frill through which the tentacles are pushed.
The left anterior tentacle (seen in the figure) is joined at its base in front of the mouth (w) to the right anterior tentacle, and similarly the left (o) and right posterior tentacles are joined behind the mouth.
According to researches in 1907 by De Selys-Longchamps, the blood is driven by the afferent vessel (af) to a crescentic lophophoral vessel (d.v.) which supplies the tentacles.
It has, moreover, been shown (see especially Goodrich, 5) that shortly before its metamorphosis, Actinotrocha develops a coelomic space which lies immediately in front of the oblique septum, and gives rise later to the cavity of the lophophore and tentacles.
Like all the other octopods it has eight arms but also has a pair of retractile tentacles for catching its prey.
It ensnares its victims in ' tentacles of terror ' before feeding them into one of its three slavering mouths.
Get out of the water as soon as you can and have someone help get any tentacles off your skin.
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Huge numbers of crinoids swarm across the gully bottoms, carefully avoiding the outstretched tentacles of the anemones.
Although I only slightly came in contact with the tentacles of the jellyfish (on my chest), the sting was VERY painful.
Moreover, he had dreams of the sort that cling to the emerging minds like the dim tentacles of an octopus.
His adventures include escapades with a number of characters, including Sandy Cheeks, Squidward Tentacles, Mermaid Man and Barnacle Boy.
Jellyfish venom is delivered by barbs called nematocysts, which are located on the creature's tentacles and penetrate the skin of people who brush up against them.
Also, jellyfish tentacles may be transparent and up to 120 feet (36.5 m) long; therefore, great caution must be exercised whenever a jellyfish is sighted nearby.
The jellyfish is surrounded by tentacles that are covered in venomous sacs.
Oftentimes, alkali-venom tentacles may be stuck to the surface of the skin.
Any tentacles remaining on the skin will need to be removed carefully (preferably with gloves) to avoid further exposure to the poisonous venom.
Carefully remove tentacles if stung to avoid subsequent stings.
Just below the crown of tentacles, however, the body widens out to form a " head," termed the hydranth (a), containing a stomach-like dilatation of the digestive cavity.
On the upper face of the hydranth the crown of tentacles (t) surrounds the peristome, from which rises the conical hypostome, bearing the mouth at its extremity.
The greatest variation, however, is seen in the tentacles.
With the exception of these forms, reduced for the most part in correlation with a semi-parasitic mode of life, the tentacles are usually numerous.
It is rare to find in the polyp a regular, symmetrical disposition of the tentacles as in the medusa.
It is usual for the umbrella to have an even, circular, uninterrupted margin; but in the order Narcomedusae secondary down-growths between the tentacles produce a lobed, indented margin to the umbrella.
The marginal tentacles are rarely absent in non-parasitic forms, and are typically four in number, corresponding to the four perradii marked by the radial canals.
Interradial tentacles may be also developed, so that the total number present may be increased to eight or to an indefinitely large number.
In places the nematocysts may be crowded so thickly as to form a tough, supporting, " chondral " tissue, resembling cartilage, chiefly developed at the margin of the umbrella and forming streaks or bars supporting the tentacles (" Tentakelspangen," peronia) or the tentaculocysts (" Gehorspangen," otoporpae).
The distal portions form the muscles of the tentacles.
One, the " upper " or ex-umbral nervering, is derived from the ectoderm on the ex-umbral side of the velum; it is the larger of the two rings, containing more numerous but smaller ganglioncells, and innervates the tentacles.
The sense-cells form, in the first place, a diffuse system of scattered sensory cells, as in the polyp, developed chiefly on the manubrium, the tentacles and the margin of the umbrella, where they form a sensory ciliated epithelium covering the nerve-centres; in the second place, the sense-cells are concentrated to form definite sense-organs, situated always at the margin of the umbrella, hence often termed " marginal bodies."
The whole structure is innervated oho+ like the tentacles, from1 j' the ex-umbral nerve-ring.
We can distinguish (I) digestive endoderm, in the stomach, often with special glandular elements; (2) circu-, latory endoderm, in the radial and ring canals; (3) supporting endoderm in the axes of the tentacles and in the endodermlamella; the latter is primitively a double layer of cells, produced by concrescence OC-- = w.?"
Here the medusoid, attached by the centre of its ex-umbral surface, has lost its velum and sub-umbral muscles, its sense organs and mouth, though still retaining rudimentary tentacles.
If the three principal organ-systems of the medusa, namely mouth, tentacles and umbrella, be considered in the light of phylogeny, it is evident that the manubrium bearing the mouth must be the oldest, as representing a common property of all the Coelentera, even of the gastrula embryo of all Enterozoa.
Next in order come the tentacles, common to all Cnidaria.
In some polyps the tentacles are webbed at the base, and it was supposed that a medusa was a polyp of this kind set free, the umbrella being a greatly developed web or membrane extending between the tentacles.
Mechnikov considered the plate thus formed at the base of the polyp as equivalent to the umbrella, and the body of the polyp as equivalent to the manubrium, of the medusa; on this view the marginal tentacles almost invariably present in medusae are new formations, and the tentacles of the polyp are represented in the medusa by the oral arms which may occur round the mouth, and which sometimes, e.g.
The body bears tentacles, but shows no division into hydrorhiza, hydrocaulus or hydranth; it is temporarily fixed and has no perisarc. The polyp is usually hermaphrodite, developing both ovaries and testes in the same individual.
When fully developed the medusa is characterized by the sense organs being composed entirely of ectoderm, developed independently of the tentacles, and innervated from the sub-umbral nerve-ring.
The gymnoblastic polyp usually has a distinct perisarc investing the hydrorhiza and the hydrocaulus, sometimes also the hydranth as far as the bases of the tentacles (Bimeria); but in such cases the perisarc forms a closely-fitting investment or cuticule on the hydranth, never a hydrotheca standing off from it, as in the next sub-order.
The head in most cases bears two pairs of tentacles.
It carries two pairs of cephalic tentacles and a pair of sessile eyes.
Shell external and conical; anterior tentacles form a frontal veil; ctenidium extending only over right side; a distinct osphradium.
The reduction of the tentacles in all these forms may be correlated with their mode of life, and especially with living in a constant current of water, which brings foodparticles always from one direction and renders a complete whorl or circle of tentacles unnecessary.
A further stage in evolution is that the muscle-cells lose their connexion with the epithelium and come to lie entirely beneath it, forming a sub-epithelial contractile layer, developed chiefly in the tentacles of the polyp. The of the evolution of the ganglioncells is probably similar; an epithelial cell develops processes of nervous nature from the base, which come into connexion with the bases of the sensory cells, with the muscular cells, and with the similar processes of other nerve-cells; next the nerve-cell loses its connexion with the outer epithelium and becomes a sub-epithelial ganglion-cell which is closely connected with the muscular layer, conveying stimuli from the sensory cells to the contractile elements.
In this order the radial canals are represented only by wide gastric pouches, and in the family Solmaridae are suppressed altogether, so that the tentacles and the festoons of the ring-canal arise directly from the stomach.