STRUCTURE OF DOGFISH 



613 



The intestine opens into the cloaca by a short rectum 

 bearing a finger-Uke rectal gland on its dorsal wall. The 

 liver has two large lobes and a small median one, in which 

 the gall-bladder is embedded. Into the upper part of the 



QB 



Fig. 348. — Dorsal view of brain 

 of Acanthias vulgaris. — After 

 Purser. 



O.B., .Olfactory bulb ; CBR., cerebral 

 hemispheres ; P., pineal body rising 

 from optic thalami ; OP.L., optic 

 lobes; CBL., cerebellum ; R.B., resti- 

 form bodies; M.O., medulla oblon- 

 gata ; SP.C, spinal cord; /('., V., 

 VII., and X., roots of these nerves. 



intestine open the bile-duct and the duct of the pancreas. 

 Occasionally the pancreas is absent as a distinct organ. A 

 dorsal mesentery supports the viscera. 



Circulatory system. — (i) The blood from the heart 

 passes forward through a contractile conus arteriosus with 

 four longitudinal rows of three valves into the ventral aorta. 



