1905.] 



ARTERIAL SYSTEM IN SAUROPSIDA. 



65 



form. In one of the two specimens at my disposal, I could not 

 see veiy well the actual mode of junction of the vertebi-al arteries 

 with the basilar. In the other it was plain and very complicated. 

 The basilar artery itself divides and immediately reunites, thus 

 forming a circle ; the two vertebral s join below this circle, and 

 from the low^er surface of this transversely running trunk two 



Text-fig. 18. 



Text-fie-. 19. 





UL 



Text-fig. 18. — Tupinam7)is niffropitnctatus. Veutral aspect of brain, showing chief 

 arteries. Lettering as in text-fig. 16. 



Text-fig. 19. — Pytlion molitriis. Ventral aspect of brain, showing chief arteries. 

 V. Vertebral arteries. Other letters as in text-fig. 16. 

 To the right of the figure is an enlarged representation of the junction 

 of the vertebral arteries with the basilar. 



branches are given off, each of which joins one side of the circle 

 already referred to. I should not like to lay undue stress upon 

 the fact as absolutely characteristic of Python, since the arrange- 

 ment was not obvious in one specimen through deficiency of 

 injection. 



Piioc. ZooL. See— 1905, Vol. II. No. V. 5 



