1908.] ox THE ANATOMY OF SNAKES OF THE GENUS CORALLUS. 135 



2. A Comparison o£ the Neotropical Species o£ Corallus, 

 C. cookii, with C. madagascariensis ; and on some 

 Points in the Anatomy of Corallus camnus. By Frank 

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



[Received February 7, 1908.] 



(Text-figures 21-27.) 



Contents. p^^^ 



(1) A Comparison of Corallus cookii with C. madagascariensis 135 



(2) Some Notes upon the Anatomy of Corallus caninus 154 



(1) A Comparison of Corallus cookii and 



C. MADAGASCARIENSIS. 



Some little time since * I contributed to the ' Proceedings ' of 

 this Society notes upon the visceiul anatomy of the Madagascar 

 Tree-Boa, Corallus viadagascariensis. This particular species is 

 the only one out of five or six species which inhabits Madagascar. 

 The rest are all Neotropical in habitat. Tlie distribution of this 

 genus Corallus is therefore remarkably like that of the allied 

 genus Boa, of which there are also both Neotropical and Mada.gascar 

 species. This very remarkable distribution rendei'S it particularly 

 desirable to scrutinise carefully the structure of the species of 

 these two genei'a, which inhabit two such mutually distant regions 

 of the world. It is possible that both these instances may prove 

 to be parallel to the case of Solenodon and Centetes, which were 

 at one time thought to be more nearly allied than systematists ai-e 

 now inclined to allow, and I shall give reasons for believing that 

 the two species of Corallus are different in structure. Dr. Gadow 

 observes t that Boa dumerili and Boa madagascariensis, " both 

 of Madagascar, cannot be separated from the genus Boa." 

 Mr. Boulenger, in the British Museum Catalogvie of Serpents +, 

 places Corallus madagascariensis alone in a special subdivision 

 of the genus on account of the comparative length of its tail ; 

 but he is unable to find in external characters any features 

 of sufficient weight to justify its generic separation from the 

 remaining serpents placed by him and by others in the same 

 genus. I am able in the present communication to lay some 

 facts before the Society which bear upon this matter ; and, as I 

 have had the opportunity duiing the past year of dissecting no 

 less than seven examples of an Ameiican species, Corallus cookii, 

 I am able to say something about the variations shown in the 

 anatomy of this snake ; the fact that I have been able to check 



* " Contrilmtions to the Kuowledsrc of the Vascular System, itc, in Ophidia," 

 r. Z. S. liK)(i. p. ohx 

 f C:niilii-id':c X;i(. Hist. vol. viii. Auiph. & Kept. p. 602. 

 .t Cataloj;-ue otSiwkcs. \iil. i. p. 99. 



