1904.] 



ANATOMY OF CERTAIN SNAKES. 



109 



named snake this arrangement of the intercostals persists to the 

 end of the body, in Eryx jaculus another arrangement comes into 

 force further down the body which is displayed in the drawing 

 reproduced as text-fig. 20, p. 110. First of all, i. e. anteriorly, 



Text-fig. 19. 



Part of intercostal arterial system of Mri/xjacuhis. 



Ao., right, Ab., left aortic arch ; oes., OBSophageal twigs ; P.v., posterior 

 vertebral artery ; V., vertebral artery. 



the intercostal arteries begin to arise regularly from the aorta, 

 and, when they reach the parietes, do not form short longitudinal 

 vessels which give off paired branches to several successive 



