614 Mil. a. A. BOUIiENGKU ON TUB [JuilC 2, 



have been generous enough to assist the work by a donation of 

 £70. This has been of considerable assistance in the purchase of 

 paper, material, &e. 



A manuscript of this nature is necessarily imperfect for any one 

 genus until the whole literature has been gone through. As far as 

 possible it is compiled from 1758 upwards, but often a side issue 

 tiikos the compiler on even into the present year. Every book 

 vvlien completed is ticked off in some well-known Catalogue, and a 

 catalogue slip is made, so as to allow of an alphabetical register. 



It is believed that the plan adopted for preparing an ' Index 

 Generum et Specierum Animalium ' is so arranged and so carried out 

 that the work is completed day by day so far as it goes, and that 

 it would be easy for any individual to continue the carrying out of 

 the scheme to-morrow should there be occasion to do so. 



S. Remarks on the Dentition of Snakes and on tlie Evolution 

 of the Poison-fangs. By G. A. Boulenqer, P.R.S. 



[Received May 26, 1890.] 



By the researches of Mr. G. S. West on the buccal glands of 

 Snakes, the results of which appeared in the last voliune of tliese 

 'Proceedings' (1895, p. 812), a further blow has been dealt to the 

 taxonomic division of Snakes into poisonous and non-poisonous, a 

 division I may claim to have been the first to abandoa '. 



Certain statements in the above-mentioned paper, concerning the 

 dentition, call for criticism. In the Introduction to the first volume 

 of the ' Catalogue of Snakes,' it was pointed out that the indication 

 of the number of teeth should refer to the full set in each maxillary, 

 as " few specimens show the complete dentition, gaps occurring here 

 and there, but shallow sockets in the bone indicate the bases of 

 the missing teeth." This has not been taken into consideration 

 by Mr. West, who erroneously ascribes diastemata between the 

 solid teeth to Leptodira, these being simply due to loss of teeth 

 in the specimen examined by him ; the maxillary teeth form an 

 uninterrupted series in that genus. Besides, it will be seen, by 

 comparing his statements and iigures with the indications in the 

 ' Catalogue of Snakes,' that, in most cases, the number of teeth 

 given by him is lower than the actual full set. The error I point 

 out is an important one, since, were the teeth counted in that 

 manner, hardly any two specimens of the same species would show 

 the same number. It even often happens that every alternate 

 tooth having dropped out, the jaw appears, on a superficial exami- 



' My views have been accepted by Pi-of. Oope, wlio, in his latest classification 

 (Tr. Amer. Philos. Soc. xviii. 1895, p. 186), observes: " One result is that I am 

 able to confirm the conclusion of Boulenger, i. e. that the Oolubriform venomous 

 Snakes, the Proteroglypha, do not differ in any fundamental respect from tlie 

 non-venomous Colubridse." Dr. Giinther (Biol. C.-Am., Rept. 1895), on the 

 other hand, still adheres to the old arrangement, as evinced by his continuing 

 to intercalate the Boidas, the most generalized of all Ophidians, between the 

 Opisthoglypha and the Proteroglypha. 



