926 MR. F. E. BEDDARD ON TWO SPECIES [Dec. 14, 



§ Renal Arteries. 



In the series of papers dealing with the anatomy of the Boiflee, 

 to which I have referred in the course of the present communica- 

 tion, I have many times mentioned the fact that among the 

 Boidfe the existence of but a single artery to each kidney is the 

 rule, with but slight exceptions. 



It may now be safely asserted that this diminution in the 

 number of the renal arteries, which never exceed two to each 

 kidney, and that only in the genus Eryx, is a characteristic of the 

 group. Boa occidentalis is no exception to this rule, and I found 

 in the case of one kidney but one renal artery, which was fol- 

 lowed carefully from its origin from the aorta down to the end 

 of the kidney, which it first touches at the anterior end of that 

 viscus. In the case of the other kidney, it seemed to me (and 

 though I am not quite positive as to the fact, I am very nearly 

 sure) that the single renal artery arose not independently from 

 the aorta, but as a branch of one of the intestinal ai"teries. Un- 

 fortunately, the condition of the renal arteries is one of the points 

 which I did not ascertain in the species Boa madagascariensis. 



§ Alimentary Viscera. 



There is frequently an inequality between the two lobes of the 

 liver in Serpents, and among them in the Boidse. Up to the 

 present, I believe that the most maiked case of inequality in 

 length between these two lobes occurs in Coralhis madagas- 

 cariensis, where I have described it. 



In that snake * the long thin " tail " of the liver was some four 

 inches long. I have now to record the same kind of inequality 

 in Boa occidentalis, where, however, it is not so marked as in the 

 species of Corallus, but still very striking. In the example of 

 Boa occidentalis which I dissected, the " tail " measured about 

 3 inches, as is shown in the accompanying figure (text-fig. 285). 

 The stomach of the same snake, which was in a contracted con- 

 dition, showed on each side a very marked tfenia. 



It is well known that the small intestine of snakes is the only 

 region of the gut which is folded, the rest of the alimentary 

 canal being sti"aight. As a contribution to our knowledge of the 

 extent to which this folding takes place, I made some measure- 

 ments of the small intestine of Boa madagascariensis. In this 

 snake the coiled small intestine lay between the pancreas and the 

 region of the testis. It measured no less than 31 inches. The 

 length of the body of the reptile between the points which lodged 

 this coiled gut was only 4 or 5 inches. I did not make a corre- 

 sponding observation upon Boa occidentalis. 



* " Contributions to the Knowleds^e of the Vasculai- and Eespiratoiy Systems in 

 the Ophidia, &c.," P. Z. S. 1906, p. 517. 



