1904.] ox THE CIRCULATORY SYSTEM IX THE OPHIDIA. 331 



5. Contributions to our Knowledge of tiie Circulatory 

 ■ System in the Ophidia. By Fraxk E. Beddard, 

 M.A., F.R.S., Prosector to the Society. 



[Received Februaiy 4, 1904.] 



(Text-figures 67-78.) 



So far as I am a,Avare, the detailed accounts of the ai'tei-ies and 

 veins in Snakes, wliich have been published by pi-evious observers, 

 are comparatively few in number, though of course a great deal 

 has been ascertained about the more important arteiies and veins 

 in a considerable number of types. I have therefore attempted 

 in the following remai'ks to embody, as briefly as possible, the 

 facts which I have verified in a number of difiei-ent snakes which 

 have been specially injected with a coloured sidjstance for my 

 purpose. My observations have chiefly been made upon the 

 arterial system, though I am able to add something to our know- 

 ledge of the details in the 'venous system here and thei^e. For 

 the most part the species of snakes which I have examined differ 

 from those studied by previous observers. I have, however, come 

 to the conclusion that a vast amount of work in this bi'anch 

 remains to be accomplished before the knowledge of the circu- 

 latory system is at all adequately known in detail. For I find 

 that in the summary given in Bronn's ' Thier-Reich'* the details 

 are not always fully stated, not indeed through omissions to report 

 upon existing literature, but through the absence of great detail 

 in that literature. Many of the older writers, for instance, have 

 only dealt with cei'tain regions of the artei'ial system. Thus 

 Rathke t, writing upon the single or double condition of the 

 carotid, gives also much information upon the arteries of the head 

 and neck in general ; and his account is the completest original 

 account known to me of these arteries, though in Bronn's ' Thier- 

 Reich' it is made still more complete by the incorporation of 

 other work., Bi-andtl again has concerned himself with the 

 persistence of a ductus botalli joining the carotid and the left 

 artei'ial aortic ai'ch ; while Hochstetter § has figured and described 

 portal veins. The latter authority has compiled an excellent list 

 of previous memoirs dealing with the venous system. The list 

 given in Bronn is also most useful. 



In the present paper I attempt to do for a number of diffei'ent 



* ' Klassen unci Ovduiuigen des Thier-Reiclis,' Bd. vi. Eeptilien, Abth. iii. Sdilangen. 

 Leipzig, 1890. Tlie older and well-known works of Meckel, Cuvier, and Milne- 

 Edwards contain a good many facts. 



f " Bemerkungen iiber die C'arotiden der Schlangen," Denksclir. k. Akad. Wieii, 

 xi. Abtli. 2, p. 1 (1856). Tliis memoir lias no plates or figures. 



X " Ueber einen eigentbiimlichen spater meist obliterirenden Ductus Carotis dor 

 gemeinen Kreuzotter Pelias herns," Bull. Ac. Imp. Sci. St. Pctersbourg, ix. 1866, 

 p. 274. 



§ Morph. Jahrb. six. (1893). 



