534 



CEPHALOPODA. 



upper part of an oval gizzard (m, Jig. 219) 

 situated at the bottom of the palhal sac. 

 Close to where this tube enters, the intestine 

 (n, Jig. 219) is continued from the gizzard, 

 and after a course of a few lines communicates 

 with a small round laminated pouch or ap- 

 pendage (p, Jig. 219) analogous to the spiral 

 co3cum of the Cuttlefish, into which the biliary 

 secretion is poured : from thence the intestine 

 is continued, twice bent upon itself, but with- 

 out varying materially in its dimensions, to its 

 termination (o, jig. 219). In this course it 

 first ascends for about an inch and a half, 

 then makes a sudden bend down to the bottom 

 of the sac, and returns as suddenly upon itself, 

 passing close to the pericardium, and terminat- 

 ing between the roots of the branchiae. 



The alimentary canal is every where con- 

 nected to the parietes of the abdomen by 

 numerous filaments ; the only trace of a me- 

 sentery exists between the two last portions 

 of the intestine, which are connected together 

 by membranes including the ramifications of 

 an artery and vein.* 



The longitudinal rugae, into which the 

 lining membrane of the oesophagus is 

 thrown, disappear at its entrance into the 

 crop. The muscular coat of the crop con- 

 sists of an exterior layer of close-set circu- 

 lar fibres and an inner layer of more 

 scattered longitudinal ones. The lining 

 membrane is thin but tough, with a 

 smooth surface : when the cavity is empty, 

 it is probably thrown into longitudinal 

 folds by the action of the circular fibres. 



In the canal which leads to the gizzard, 

 the lining membrane puts on a villous 

 appearance and is disposed in distinct 

 close-set longitudinal rugae. 



The gizzard is girt by two broad radiate 



muscles, of the thickness of two lines, arising 

 from opposite tendons : it is lined by a thick 

 cuticular membrane, delicately furrowed and 

 adapted to numerous fine ridges which tra- 

 verse longitudinally the whole interior of the 

 cavity. This, as is commonly found in gizzards, 

 was detached from part of the parietes and 

 adhered very slightly to the remainder. 



The pyloric orifice is close to the cardiac, 

 and is guarded by a valve, to prevent a too 

 ready egress of matter from the gizzard.* 



The globular cavity (p, Jig. 219) which 

 communicates with the intestine at a little dis- 

 tance from the pylorus, is occupied with broad 

 parallel laminae, which are puckered trans- 

 versely, so as to increase their surface for vas- 

 cular ramifications ; their texture under the 

 lens is follicular and evidently fitted to secrete. 

 The bile enters this cavity at the extremity 

 furthest from the intestine by a duct large 

 enough to admit a common probe. The two 

 laminae on each side the entrance of the duct 

 increase in breadth as they approach the in- 

 testine, and are continued in a curved form 



Fig. 220. 



Alimentary Canal of the Povlp.\ 



* In the specimen of the Nautilus from which 

 the preceding account is derived, the whole alimen- 

 tary canal was filled with fragments of some species 

 of crab, among which portions of branchiae, claws, 

 and palpi, were distinctly recognizable. The crop 

 in particular was tensely tilled with these substances, 

 and the capability of propelling such rude and 

 angular particles through a narrow canal in the 

 gizzard, without injury to the thin tunics of the 



preparatory cavity, is a remarkable example of the 

 superior powers of living over dead matter. 



* The contents of this part of the alimentary 

 canal were in smaller pieces than in the crop, 

 but of the same nature ; the fragments ofshell were 

 comminuted apparently by mutual attrition, as there 

 were no particles of sand or pebbles present. 



t From Ferussac's Monograph on the Cephalopodes 

 Acetabuliferes. 



