. Elements of conchology / Prepared for the use of schools and colleges. Mollusks. DIGESTION IN CEPHALOPODS. 23 7. The apparatus of digestion is very complicated. The mouth is surrounded by a circular lip, and armed with two ver- tical mandibles, which closely resemble the beak of a parrot ; they are set in motion by powerful muscles. A fleshy tongue, furnished with papillse and many horny pieces, occupies the in- terior of this cavity, and is attached to a particular cartilage. Salivary glands, the number and arrangement of which vary a little, surround the pharynx and oesophagus, and pour in
. Elements of conchology / Prepared for the use of schools and colleges. Mollusks. DIGESTION IN CEPHALOPODS. 23 7. The apparatus of digestion is very complicated. The mouth is surrounded by a circular lip, and armed with two ver- tical mandibles, which closely resemble the beak of a parrot ; they are set in motion by powerful muscles. A fleshy tongue, furnished with papillse and many horny pieces, occupies the in- terior of this cavity, and is attached to a particular cartilage. Salivary glands, the number and arrangement of which vary a little, surround the pharynx and oesophagus, and pour into the alimentary canal the product of their secretion. The oesopha- gus contracts in general, and before terminating in the stomach, presents a large dilatation or crop {fg. 10, j); but some- e gs j gs /â br times, this first digestive pouch is wanting. Com- monly the stom- ach is in the form of an elongated sack ; its parietes are muscular, and its structure re- minds us of the ^ gizzard of birds. A third cavity (s) ^ succeeds this or- ^^ gan, which, in di- branchial cepha- lopods, is in the form of a coecum spirally folded, while in the tetra- branchial, it as- sumes that of a spherical sack in- ternally lamella-. Fig. 10.âVISCERA OF A TOULPE. Explanation of Fig. 10.âViscera of a poulpe :âj. the crop situated be- neatli the cephalic cartilage ;âgs. inferior salivary glands ;ââ¢/. mass formed by the liver and ink-bag-;âe. excretory duct of the ink-bag going to empty in the funnel;ât. this funnel or tube ;â7n. the open mantle ;âs. the coecum spirally folded ;âi. a part of the intestine, the rest being removed to show the organs situate beneath ;âo. the oviducts ;âc. the heart;âa. the inferior aorta ;âas. the superior aorta ;âvb. the branchial veins ;âhr. the branchise; âcl. the partition by which these organs adhere to the parietes of the re- spiratory cavity ;âab. the branchial arteries ;âcb. venous sinus or branchial hearts ;âv. vense cavoe ',âftn. mu
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectmollusks, bookyear184
