The mouth opens into a muscular pharynx lined by a thick cuticle.
The mouth is minute and the pharynx is always suctorial, never gizzard-like.
There is no armed protrusible pharynx, such as exists in some other Chaetopods.
Muscular fibres connected with the suctorial pharynx are in Limulus inserted into the entosternite, and the activity of the two organs may be correlated.
Huxley, " Pharynx of Scorpion," Quart.
Macmillan & Co., Ltd.) b, bristle; cs, caudal spine; ph, pharynx; s s', the spines on the two segments of the proboscis; sg, salivary glands; st, stomach.
Behind this point there is a muscular pharynx or gizzard, which communicates with the wide intestinal tract.
The pharynx projects freely into the atrium; it is surrounded at the sides and below by the continuous atrial cavity, but dorsally it is held in position in two ways.
A buccal cavity, a pharynx, an oesophagus and an intestine are always distinguishable.
Pharynx, and he sums up their relationship to the Annelids by thestatement that to a certain extent the Nemertines represent Turbellaria which in the course of time have copied certain features of an Annelid character.
The gill-slits may be stated briefly as follows: - (a) the presence of two kinds of branchial bars in all species and also of small cross bars (synapticula) in many species; (s) numerous gill slits, from forty to more 1 - _ than a hundred pairs; (y) the addition of new gill-slits by fresh perforation at the posterior end of the pharynx throughout life.
When they are arranged in uniserial or biserial rows the genital ducts open into or near the branchial grooves in the region of the pharynx and in a corresponding position in the post-branchial region.
The digestive system consists of a simple or bifurcated sac, opening through the mouth by means of a "pharynx bulbosus," adapted to act primarily as a sucker, and secondarily, when drawing blood, as an aspirator.
The pharynx or stomodaeum is still small, the foot not yet prominent.
At the anterior end the head is differentiated; it bears the sense-organs, and contains the muscular pharynx within which is the radular apparatus.
The branched intestine (G) is drawn on one side of the animal only; it opens to the exterior by means of a pharynx (not shown).
The study of Rhabdocoels (7) has led to the important discovery that the rudiment of the gonads and that of the pharynx are the first organs to appear, and that the alimentary sac arises independently of them.
Along this channel the nectar is drawn into the pharynx and passes, mixed with saliva, into the crop or "honey-bag"; the action of the saliva changes the saccharose into dextrose and levulose, and the nectar becomes honey, which the bee regurgitates for storage in the cells or for the feeding of the grubs.
Together with currents of water induced by the action of the vibratile cilia which are abundant along special tracts on the sides and roof of the vestibule of the mouth and in the walls of the perforated pharynx ("ciliary ingestion").
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.
New clefts continue to form at the posterior end of the pharynx during the adult life of the animal.
H, The acrembolic (= pleurecbolic) pharynx of a Chaetopod fully introverted.
Pharynx suctorial; no radula; branchial rosette on the dorsal surface, above the mantle-border.
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.
It has a pharynx and short straight digestive sac: and its mesenchymatous cavities are filled with germ-balls in various stages of development.
The mouth opens through a narrow pharynx (p) into a chamber which is (as in Crustacea) at once crop and gizzard, the mastax (ma), whose thickenings are imbedded in the posteroventral wall.
The mouth begins as a funnel, continued into a narrow pharynx, which in Flosculariaceae is prolonged intoa slender tube hanging From C. T.
Gastrulation takes place by epiboly, and the stomodaeum (oral invagination - mastax pharynx) takes place in two stages of the region of the closed blastopore.
- " Errant" Polychaetes with well-marked prostomium possessing tentacles and palps with evident and locomotor parapodia, supported (with few exceptions) by strong spines, the aciculi; muscular pharynx usually armed with jaws; septa and nephridia regularly metameric and similar throughout body; free living and predaceous.
Parapod.ia hardly projecting; palps of prosomium forming branched gills; no pharynx or eversible buccal region; no septa in thorax, septa in abdomen regularly disposed.
In the latter case, the numerous bands of muscle attaching the pharynx to the parietes have obliterated the regular partition by means of septa.
19, F) which tie the axial pharynx to the adjacent wall of the apical part of the introvert.
Supposing the tube to be completely introverted and to commence its eversion, we then find that eversion may take place, either by a forward movement of the side of the tube near its attached base, as in the proboscis of the Nemertine worms, the pharynx of Chaetopods and the eye-tentacle of Gastropods, or by a forward movement of the inverted apex of the tube, as in the proboscis of the Rhabdocoel Planarians, and in that of Gastropods here under consideration.
Pharynx and oesophagus are concealed in the head.
Pharynx suctorial; branchiae surrounding the body, between the mantle and foot.
(Lankester.) ph, Pharynx (stomodaeal inattachment to the ecto vagination).
The ciliated band of the left side of the velar area is indicated by a line extending from v to v; the foot f is seen between the pharynx ph and the pedicle of invagination pi.
This bilobed sac becomes entirely the liver in the adult; the intestine and stomach are formed from the pedicle of invagination, whilst the pharynx, oesophagus and crop form from the stomodaeal invagination ph.
- The alimentary canal in Scorpio, as in Limulus, is provided with a powerful suctorial pharynx, in the working of which extrinsic muscles take a part.
They ingest the mucus and, to some extent, the blood of their host by the aid of a sucking pharynx through which the food passes into the bifurcated alimentary sac and its branched caeca.
The head of the insect contains a muscular pharynx by means of which the blood from the wound inflicted by the proboscis (labium) is pumped into the alimentary canal and the so-called sucking-stomach.
26, where the pharynx is widely open and the foot prominent.
There is also felt a sense of constriction in the pharynx, due to the action of the drug on its muscular fibres.
Two pairs of glands open into the buccal cavity, and at the junction of pharynx and oesophagus is another pair called the sugar glands.
The mouth is terminal or subterminal; there is a weak sucking pharynx situated behind the brain, and a long intestine lying along the medio-ventral body-cavity; it ends in a cloaca which receives the vasa deferentia in the male.
This may be associated with mud-eating habits; but it is not wholly certain that this is the case; for in Chaetogaster and Agriodrilus, which are predaceous worms, there is no protrusible pharynx, though in the latter the oesophagus is thickened through its extent with muscular fibres.
So has the acrembolic pharynx of Chaetopods, if we consider the organ as terminating at that point where the jaws are placed and the oesophagus commences.
Pharynx evaginable, with suckers.
Of any kind; a short evaginable pharynx, bearing paired conical buccal appendages or " cephalocones."
A, Dorsal view showing the nervous system and digestive system; a, mouth; b, pharynx; c, d, e, gut; E, post-genital union of two limbs of gut; f, excretory pore; g, vaginal pore; h, j, k, brain and nerves; 1, dorsal nerves; m, ventral nerves; n, adoral sucker; o, posterior sucker; p, hooks on posterior sucker; r, vitello-intestinal duct.
The nervous system consists of a ganglion or brain, which lies dorsally about the level of the junction of the pharynx and the stomach, a nerve ring and a segmented neutral cord.
- There is a large ganglion lying in close contact with the pharynx, proximal to the crop and on its antero-dorsal side; in Bdelloidaceae at least it is united by short connectives with a smaller postero-ventral ganglion to form a nerve collar.
On the floor of the pharynx or buccal mass is a rudimentary radula, which in many species consists of a single large tooth, bearing two small teeth or a row of teeth.
The first part of the alimentary canal consists of the pharynx or branchial sac, the side walls of which are perforated by upwards of sixty pairs of elongated slits, the gill-clefts.