22 



MR. F. E. BEDDARD ON THE 



[May 2, 



to the ai-teries of the brain, which are most satisfactorily injected 

 in my specimen and which show all the Arctoid characters*. 

 The rhomboidal area formed by the bifurcation of the anterior 

 spinal and its junction with the basilar is of considerable calibre 

 and uniform thi'oughout, as in all Carnivora, which have been 

 examined. 



The vertebral arteries are, however, peculiar in their mode of 

 joining this rhomboidal vessel. Each vertebral artery in fact 

 divides befoi-e joining the rhomboidal, and each branch opens 

 separately into it, as is shown in the accompanying figure (text- 

 fig. 8). The carotids join the circle of "Willis jiist before the 

 middle cerebral arteries are given off. 



Text-fiff. 7. 



Text-fio-. 8. 



Text-fig. 7. — Brain oi Selictis personata, dorsal aspect. 



Cr. Crucial fissure; Lat. Lateral fissure; Orh. Orbital fissure; Pc.S. Precrucial 

 fissure ; 8.S. Supra-Sj-lvian fissure. 



Text-fig. 8. — ^Brain of Selicfis 2}eTsonata, ventral aspect, witli the arterial system 

 shown in thicker and thinner black lines. The dotted lines delimit regions of 

 the brain. 



J.a. Basilar arter3'; Ca. Carotids; C'aW. Callosal arteries ; P.c. Posterior 

 cerebellar ; v.a. Vertebral arteries. 



Anteriorly the circle of Willis is completed by the fusion of the 

 two callosal arteries, that of the right side being distinctly smaller 

 than that of the left. 



* Beddard, P. Z. S. 1904, vol. i. p. 183. 



