THE CEPHALOPODA. 



449 



chamber can be fully distended without the air passing into 

 the other. 



Fig. 121.— Sepia officinalis. — c. systemic heart ; on, antprioraortn : ao', posterior aorta; 

 1. vena cava; 2, alierent branchial vessels; re, renal or-ai;s; z. appeu.iagl■^< of 

 these vessels ; 3, 4. lar^-e posterior veins biinginir blood to the afferent brauciiidl 

 vesseli^ ; 5. 6, 7. efferent branchial vessels, branchial veins,-and braucLio-cardiac 

 or auricular trunks. (After Hunter.) 



In N^cmtUus ^jompilius there are, as Valenciennes discov- 

 ered, three pairs of openings which lead from the branchinl 

 sac into chambers contained in the interior of the body. Of 

 these chambers there are five : the anterior and posterior 

 pairs are situated on each side of the rectum, and each has 

 its own opening ; the fifth, a very much larger chamber, has 

 two openings, one on each side. It is coextensive Avith thnt 

 part of the mantle which lies behind the insertion of the shell- 

 muscles and the horny band which connects them. It is 

 separated from the paired chambers bv their inner walls, and 

 these walls are traversed by the afferent branchial veins. 

 Appendages of these veins pn^ject on the one hand into the 

 paired chambers, and on the other into the single chamber. 

 The latter appendages are elongated papillae, while the for- 

 mer nre lamellar. Earthy concretions, composed mainly of 

 phosphate of lime, but which yield no trace of uric acid, are 

 usually found in the paired sacs.^ 



1 Owen, " Memoir on the Pearly ISTantilus." Van der Hoeven, " Beitracr 

 ziir Anatomic vom jVaidih/.<f pompiUvs'''' ("Archiv fnr Naturgeschiebte," 

 1857). Huxley. "On some Points in the Anatomy oi KanUlus 'pompiHm'''' 

 (" Proeeedino-'s of the Linn•T^^n f>oeietv," 1858). See also Keferstein, Bronn's 

 *'Klassen u. Orduungea," Bd. ill. (1862-'66), pp. 1390, 1319. 



