1904.] ON THE ANATOMY OF CERTAIN SNAKES. 107 



3. Notes upon the Anatomy of certain Snakes o£ the Family 

 Boidoi. By Frank E, Beddard, M.A., F.R.S., Pro- 

 sector to the Societ}''. 



[Received May 2, 1904.] 

 (Text-figures 19-23.) 



The Boidfe are held by most zoologists to occupy a place near 

 the base of the Ophidian series. This view is based chiefly upon 

 the paired lungs, the considerable rudiments of the hiiid limbs, 

 and upon some other osteological points which are duly summed 

 up by Boulenger*. The viscera also confirm this opinion; and I 

 propose in the following pages to call attention to some new 

 or little-known facts relating to the circulatory system which 

 collectively support it. 



§ Gubernaculum cordis, and Right and Left Aortce. 



No member of the genera Python, Boa, Eunectes, and Eryx 

 which I have dissected possesses any trace whatsoever of a 

 gubernaculum cordis tying down the apex of the heart to the 

 walls of the pericardium. It is not altogether unnecessary to 

 record the absence of a gubernaculum, though it has been stated 

 that the Lacertilia are to be contrasted with the Ophidia by the 

 presence in the former and the absence in the latter of this 

 gubernaculum. A more correct statement would be arrived 

 at if the word " generally " were interpolated in both 

 cases. I find, in fact, considerable vestiges of this tag in several 

 Ophidia. It occurs for example in Coronella getida. In Ccdopeltis 

 monspessulana a thin sheet of membrane runs from the ventricle 

 some little way above the apex to the vena cava and passes down 

 the latter to the posterior wall of the pericardium. 



In the Hamadryad {Ophiophagus hungarus) the covering mem- 

 brane of the heart ( = visceral layer of peritoneum) is obvious and 

 can be stripped ofi". Posteriorly, this membrane forms a tubular 

 prolongation of which one side is attached to the vena cava at its 

 entrance to the heart and to the pericardium beyond, while the 

 other is attached to the pericardium wall behind. The ventiicle, 

 therefore, near to the apex, but on one side, is attached not merely 

 to the vena cava, but also to the wall of the pericardium. 



It is impossible to speak of these structures but as a gubernaculum 

 cordis. On the other hand, it is clear that they difier somewhat 

 from the gubernaculum in the Lacertilia, which has no relation 

 to the vena cava but attaches the actual apex of the ventricle to 

 the pericardial wall, and is of more ligamentous consistency. 



The structure is therefore possibly a new one in the Ophidia, 

 on which view its total absence in the Boidse (so far as the 

 material which I have examined enables me to say) may well be 



* Catalogue of Snakes in the British Museum (Natural History), London, 1883. 



