XII 



PHYLUM MOLLUSCA 



715 



it gives origin to a much smaller aboral aorta (aort'.), which 

 -bends over the ink-sac and supplies the aboral portions of 

 the body. The arteries which lead off from the aorta? com- 

 municate by their ultimate branches with a system of capil- 

 laries, and these with a system of sinuses and veins. A large 

 median vein, the vena cava (v. cav.), runs from the head to the 

 neighbourhood of the rectum, in front of which it bifurcates 

 to form to right and left afferent branchial veins (1. off. br. v., 

 r. affilr. v.), each running through the cavity of the corresponding 



JSti 



FIG. 023. Sepia, median section through 

 the buccal mass. //. l> t \ buccal ganglia; 

 {/. stoiii. stomatogastric ganglia; trust, sup- 

 posed gustatory organ ; jatci, posterior 

 jaw ; ,/>>-, anterior jaw ; v. oesophagus ; 

 perist. peristomial membrane ; mi.!, radula. 

 (After Keferstein.) 



FIG. 624. Sepia officinalis, enteric 

 canal, a. anus ; b. d. one of the bile 

 ducts ; b. m. buccal mass ; c. caecum ; 

 i. ink-sac ; i. <L ink-duct ; j. jaws ; 1. 1. 

 liver lobes ; w. oesophagus ; p. pan- 

 creatic appendages ; r. rectum ; s. g. 

 salivary glands; st. stomach. (From 

 the (.'nnibfiiliii Sut i' rid History.) 



renal organ to the base of the gill, where it is joined by veins from 

 the aboral region. At the base of the gill the afferent branchial 

 vein becomes dilated to form a contractile sac the branchial heart 

 (/-. br. Jit.) appended to which is a rounded body of a glandular 

 character the (fj>j>< nf/ayc of the branchial heart. The afferent 

 branchial vein runs through the axis of the branchia giving off 

 branches as it goes. The blood is carried back to the ventricle by 

 a dilated contractile vessel, the auricle or efferent branchial vein 

 (/. car., r. aur.). 



