LESSON 47.] NUTRITION IN THE GASTEROPODA, ETC. 165 



719. In the Nautilus, a short pharynx (a, Fig. 266) leads to the 

 03sophagus (6), which dilates into a crop (c), with well marked lon- 

 gitudinal folds. Below this first cavity (c), a narrow tube conducts 

 to the second stomach, or muscular gizzard (d) ; this is situated on 

 the right side, and varies in its form, muscularity, and relative size, 

 and is provided with a thick, tough, coriaceous internal lining, to 

 protect it from the hard shells, and other dense 



substances taken in with the food. 



720. The muscles of the gizzard radiate from 

 around a circular tendinous part on each side, or 

 pass continuously over the sides of the cavity. 



From the left side of the gizzard a passage, 

 generally short, and wide, leads to the third 

 stomach (e), which in many Cephalopods has a 

 convoluted spiral shape, and presents internally 

 numerous transverse folds of its mucous coat. 



Passing to the left side from the third, or Nutrimentai organs, 



& m Nautilus. 



spiral stomach, the intestine (/) forms a short 

 single convolution near the left branchial heart, then ascends along 

 the fore part of the liver to terminate between two longitudinal 

 strong muscular bands near the base of the syphon, by a free external 

 orifice (g). 



721. This third gastric cavity forms (in Nautilus) a globular 

 sac, plicated internally, with parallel folds. The intestine forms a 

 short, single convolution directed downwards, then ascends to the 

 fore part of the liver, to terminate between two strong muscular 

 bands, near the base of the syphon. 



722. Destitute of a shell, as the great majority of the Cephalo- 

 pods are, they are left (apparently) without the means of protecting 

 themselves from the thousands of foes, ever ready to destroy them. 



723. Their naked, plump, soft, gelatinous bodies, offer an irresist- 

 ible temptation to every fish that swims the ocean ; to Lobsters and 

 Crabs ; and to nearly every marine animal. 



724. The* wisdom and beneficence of an all-wise Providence is 

 singularly exhibited in favor of the Cuttle-fishes, for he has given 

 them a passive means of defence, vastly more efficacious and superi- 

 or than physical power, or great warlike capabilities : he has simply 

 furnished them with a bag, full of intensely black ink ; if pursued by 

 an enemy, for even the shortest space, the creatures at once discharge 

 the contents of this bag, which instantly renders the ocean, for a 

 great space above, below, and around, exceedingly black and turbid, 



