164 ANIMAL PHYSIOLOGY. [LESSON 47. 



broad, flat, horny teeth, which serve to divide the softened vegetable 

 matter transmitted in small portions from the first stomach. 



714. The third cavity (I) of this complex series of stomachs, is 

 placed on the left side of the abdomen; it receives by several wide 

 ducts, at its pylorio orifice, the secretion of a large, lobed liver (o), 

 and of a long, single pancreatic follicle ; its inner parietes are fur- 

 nished with several sharp, horny spines, to assist in subdividing the 

 coarse food, for the purpose of admitting the solvent gastric fluids. 

 The intestine (m) forms several convolutions round the liver (o), and 

 after a lengthened course, without forming an enlargement, it opens 

 on the right side (n), near the posterior portion of the body, and 

 immediately behind the heart (q, r) and the large gills (p). 



715. In some of the Gasteropodous molluscs (as we have seen), 

 there are as many as four distinct gastric cavities ; horny teeth are 

 more or less found in the interior of one, or more, of these sacs, in 

 addition to the armature of the tongue, by teeth of various shapes 

 and sizes, which obtains extensively in this class. 



Flo 265 716. A figure of the teeth of the tongue 



of the common Whelk (Buccinum unda- 

 tum) is given in Fig. 265. In the Limpet, 

 the tongue is longer than the whole body, 

 and is covered with transverse rows of sharp 

 recurved spines, by which they are enabled 

 to file the coarse marine plants, on which 

 they subsist. 



CEPHALOPODA. 



717. These animals, for the most part, 

 are free, naked, and predaceous ; they are 

 Teeth mi^the tcmgn^of Buccin- provided with powerful organs of prehen- 

 sion, and mastication, and their short al- 

 imentary canal is furnished with highly developed salivary, biliary, 

 and pancreatic glands. The muscular bulb of the mouth contains, 

 in the naked species, two strong, curved, sharp, horny mandibles, 

 very like those of a parrot. 



718. The short muscular tongue is covered with rows of sharp, 

 horny, recurved spines (as already noticed in other molluscs), attach- 

 ed to a cartilaginous base. There are two pairs of salivary glands ; 

 an upper smaller, and an inferior larger pair both of which are con- 

 glomerated (a round mass a batt)j and tabulated (composed of 

 lobes). 



