508 MR. F. E. BEDDARD ON THE VASCULAR AND [May 1, 



and I sliall take occasion to refer in the coui-se of the following 

 notes to what is already known relating to the organs and systems 

 which I have myself examined in Boa diviniloqua. My own notes 

 chiefly refer to the vascular and respiratory systems. 



AnLerioo- Abdominal Veins. — These veins in the present species 

 of Boa retain their distinctness until within an inch of the gall- 

 bladder. Posteriorly each arises, as Gadow has figured *, from the 

 divided caudal. 



The exact arrangement in Boa diviniloqua is shown by dis- 

 section to be this : — Each half of the divided caudal vein 

 again divides into two trunks considerably behind the kidneys. 

 This occurs at a slightly different level on the two sides of 

 the body. On the left side, the division took place, in a male 

 individual measuring 52 inches from the tip of the snout to the 

 cloaca, at a point 3g inches from the cloaca and 6g inches from the 

 posterior end of the left kidney. On the other side of the body, 

 the point of separation was a trifle further forward, in correspond- 

 ence with the anterior shifting of the right kidney. Only the left 

 side is figured in the work referred to below, but the junction of 

 both anterior abdominals with the corresponding renal afiferent is 

 mentioned in the text. The figure* of Pelophilus madagascariensis 

 shows a difference from what I have found in Boa diviniloqua. 

 In the latter species, immediately after the separation of the 

 renal trunk from the caudal vein, the renal branch receives an 

 important affluent from the parietals. This is found on both 

 sides of the body. I ascertained with care the exact point of 

 entrance of this vein, since there are apparently differences among 

 the Boidas. By Gadow the vein is represented as debouching into the 

 caudal before it has divided into the renal afferent and anterior 

 abdominal. In Eunectes and Eri/x I have described and figured or 

 described the vein as opening exactly at the point of divergence 

 of the afferent renal and anterior abdominal t, or as in the present 

 species. In the example of Boa constrictor which I dissected the 

 details (text-fig. 89) are somewhat different. The two anterior 

 abdominals retain their separateness until within 4^ inches of the 

 gall-bladder. As the snake measured 70 inches from the snout to 

 the cloacal orifice, the porportions are very much the same as those 

 given above. The origins of the two posteriorly from the caudals 

 are quite symmetrical ; they are exactly opposite to each other. 

 And this is in spite of the fact that the kidneys are unsymmetrical 

 as in Boa diviniloqua. In fact the kidneys are more unsym- 

 metrical. The left kidney, which is 5| inches in length, is 12 inches 

 from the cloacal orifice. The right kidney is smaller, 4| inches, 

 and only overlaps the left kidney for the space of 1| inches. There 

 is a greater overlap in Boa diviniloqua. 



Renal Veins. — The afferent renal veins, after parting from the 

 roots of the anterior abdominal, receive affluents from the parietes. 



* In Bronn's ' Thierreich,' Bd. vi. pi. cxxxv. fig. 2v.a.s., v.a.d. 

 f " Notes upon the Anatomy of certain Snakes of the Family Boidse," P. Z. S. 1904, 

 vol. ii. p. 113, text-figs. 21, 22. 



