732 ZOOLOGY 



SECT. 



are apertures which may be the openings of salivary ducts, but 

 the existence of salivary glands has not been proved. 



The oesophagus (oes.) becomes dilated aborally into a very 

 spacious crop (cr.) for the storage of the food, consisting of small 

 prawn-like Crustaceans and small Fishes broken up by the jaws 

 and radula. This opens into a rounded stomach (stom.) having 

 very much the appearance of the gizzard-like caecum of Sepia. 

 The intestine (int.) shortly after it leaves the stomach, develops 

 a rounded caecum (ccec.) with complexly folded walls, into which 

 the ducts of the liver open. The intestine does not pass 

 straight to the anus as in Sepia, but first bends round in a 

 short coil. The ink-sac and duct of Sepia are not represented. 

 There is a very large liver divided into four main portions or 

 lobes, each of which is made up of a number of lobules. The 

 bile-ducts (b. du.), opening as above mentioned into the caecum, 

 have a series of small diverticula which may represent the pan- 

 creatic appendages of Sepia. 



Heart and Circulation. The ventricle (Figs. 642 and 643 

 vent.) is a bilobed, transversely placed, muscular sac, very similar 

 to that of Sepia. On either side there open into it two auricles 

 or efferent branchial vessels (a. or.), one from each of the four 

 ctenidia. The ventricle gives off a large main aorta (aort.), which 

 passes to the head after giving off arteries to ' the stomach, 

 the crop, the liver, and the mantle. From the aboral surface of 

 the ventricle is given off a smaller artery, the lesser aorta, which 

 immediately bifurcates. One of its branches the posterior pallial 

 artery (Fig. 642 bis, post. pall, a.) passes to the area of the 

 mantle applied to the septum, bifurcates to supply this area, 

 and gives off a branch to the siphuncle. The other anterior 

 pallial (ant. pall, a.) after giving off arteries to the intestine 

 and rectum, and to the branchiaB and osphradia passes to the 

 muscular edge of the mantle, bifurcating anteriorly. Three genital 

 arteries (gen. a. 1,2, 3), supplying the various parts of the re- 

 productive apparatus, are likewise given off directly from the 

 ventricle. 



A large vena cam (Figs. 642 and 643, ven. c.) occupies a position 

 corresponding closely with that of Sepia. It presents the re- 

 markable peculiarity of being in free communication by numerous 

 (valvular), apertures with the viscero-pericardial cavity of the 

 ccelome. At its aboral end it presents a dilatation from which 

 four afferent branchial veins (Fig. 643, a. 1. a/. /., p. I. a/., p. r. a/. } 

 r. ant, off.} two right and two left proceed to the corresponding 

 ctenidia, at the bases of which veins from the aboral region join 

 them. There are no branchial hearts. 



The renal organs (Fig. 643) are, like the ctenidia and the afferent 

 and efferent vessels, four in number, instead of two as in Sepia. 

 Each renal sac (/. neph. s., r. ncpli. s., 1. post, nc.'p'h. s., r.post. nepli. s.) 



