154 MR. F. E. BEDDARD ON THE ANATOMY [Mar. 3, 



families of Opliidia, whose characters are well known, by the 

 following distinguishing features : — 



Vestiges of hind Imihs 2^'>'ssent. Two hongs (except in Ungalia). 

 Bronchi entering lungs at a little distance from their anterior 

 extremity. Aorta giving off regidarly-jiaired intercostal arteries 

 or regularly-paired intercostals derived from feioer branches of 

 aorta. Renal artery single on each side (rarely tv:o). Umbilical 

 vein of foetus often persistent in adidt to « greater or less extent. 

 Anterior abdominal vein connected with afferent renals. Azygos 

 usually long. Postcardinals 2yresent in front of kidneys. Pancreas 

 itsually 'with sjylenic lobe. 



These characters are, for the most part, points of likeness to 

 the Lacertilia, which are more numerous in the Boidse than in 

 other snakes. They thus argue the basal position of the Boidse 

 in the Ophidian series — a view which is quite generally held. 



(2) Some Notes upon the Anatomy of Coiiallvs caninus. 



The comparisons instituted in the above account of the structure 

 of Corallus cookii are further confirmed by the dissection of an 

 example of Corallus caninus, which I have been able quite lately 

 to examine. The specimen of this extremely beautiful species of 

 Tree-Boa had been, as I understand, identified when alive by 

 Mr. Boulenger. I identified it myself when dead, before learning 

 this fact, with the help of that gentleman's ' Catalogue of the 

 Snakes in the British Museum ' *. The catalogue in question, 

 though allowing of an easy reference of the individual to its 

 proper species, does not refer to what appeal's to me to be the 

 most salient external character of the species when compared 

 with its immediate ally Corallus cookii ; that is, the much greater 

 size of the scales in the latter species. In Corallus cookii, in fact, 

 a scale upon the dorsal surface near to the middle line measured 

 4 mm. in length ; a scale from a corresponding position in C. caninus 

 measured only 2 mm. The pitting of a much greater number of 

 the labial scales than in C. cookii is another character of this 

 species. I found that in the individual examined by myself the 

 first lower labial of one side was slightly pitted. This does not 

 appear to be always the case. The mental groove is longer in 

 this snake than in C. cookii. It is bordered by fifteen scales on 

 each side. Thus there is an exaggeration of the characters of 

 C. cookii, and not an approach towards C. inadagascariensis. On 

 the other hand, the short tail of C. caninus (the length to the 

 cloaca, was 34 inches, that of the tail 5| inches) is an approach 

 to the condition observable in C. madagascariensis. The anal 

 claws were small, and, on account of their white colour, incon- 

 spicuous. Each lay between two scales in front and one behind, 

 and the area of implantation was rather bare. 



I have given reasons for regarding the position of the viscera 



* Vol. i. London, 1893, pp. 99 & 102. 



