Elementary text-book of zoology. Special part: Mollusca to man / by C. Claus ; translated and edited by Adam Sedgwick ; with the assistance of F.G. Heathcote.
- Carl Friedrich Wilhelm Claus
- Date:
- 1897
Licence: Public Domain Mark
Credit: Elementary text-book of zoology. Special part: Mollusca to man / by C. Claus ; translated and edited by Adam Sedgwick ; with the assistance of F.G. Heathcote. Source: Wellcome Collection.
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![BCAPHOPODA. 2?» (fig. 506). The body possesses a saccular mantle, like the shell open at both ends, and a trilobed foot; the foot is protruded through the larger of the openings of the shell from the anterior opening of the mantle, the margin of which is thickened. A separated cephalic region is not present, but there is an egg-shaped projection in the mantle cavity, at the apex of which is placed the mouth, surrounded by eight leaf-like labial appendages. The buccal armature con- sists of a lateral (right and left) rudimentary jaw, and a tongue beset with five rows of plates. The alimentary canal is divided into a buccal cavity, oesophagus, stomach with large liver, and an intestine, which after several coils closely pressed together, opens behind the foot into the middle of the mantle cavity. The circulatory organs are reduced to two mantle vessels and a complicated system of wall-less spaces of the body Fig. 606.—Dental ivm Tarentinum (after ^. * Lacaze-Duthiers). Respiration is effected bv Animal without . „ „ ,, . % shell from right the surface of the mantle and side, p, foot; Mt, a]s0 by filiform tentacles, circular muscle of , which arise from two ridges (cervical collar) behind the liead-like buccal prolongation. The kidney lies round the rectum, and opens by two openings placed on the right and left of the anus. The nervous system consists of three groups of ganglia, of which the pedal ganglion beat's two otocysts. Eyes are absent. The numerous ciliated tentacles serve as tactile organs. The Scaphopoda are dioecious. The ovaries and testes are un- paired finger-shaped lobed glands, which are placed behind the liver and intestine, and open to the exterior with the right kidney. mantle; M,longi- tudinal muscle ; Br, gills; N, kid- ney; L, liver; G, generative gland. Fig. 507.—Larva of Denla- limn (after Lacaze-Du- thiers). a, young larva with first rudiment of shell (S). b, Older larva seen from the dorsal sur- face ; T, tentacle collar; Go, cerebral ganglion; Ot », oesophagus ; L, Uver.](https://iiif.wellcomecollection.org/image/b2813378x_0031.jp2/full/800%2C/0/default.jpg)
