THE LOWER VEilTEBRATA. 



177 



OAJt'TAL 



vessels have 

 their blood 

 returned into 

 different ef- 

 ferent vessels. 

 From the 

 point where 

 the first two 

 of these nine 

 vessels join, a 

 carotid artery 

 is given off 

 to the head. 

 The four 

 efferent ar- 

 teries unite 

 into a median 

 dorsal aorta, 

 from which 

 arise paired 

 subclavian 

 arteries (to 

 the pectoral 

 fins), no less 

 than four 

 median ar- 

 teries to the 

 alimentary 

 canal (cceliac, 

 anterior me- 

 senteric, lieno- 

 gastric and 

 posterior me- 

 senteric), a 

 paired me- 

 tameric series 

 of small ar- 

 teries to the 

 body - wall ; 



renals, to the kidneys ; and a small pair of iliacs to the 

 ZOOL. 12 



Fig. 92. CIRCULATION OF DOGFISH. 



To bring the arteries into their proper position the right side 

 of the diagram should be folded over, so that the dorsal 

 aorta comes into the same line as the median posterior 

 cardinal sinus. 



