614 MR. G. A. BOULENGER ON THE [June 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 faras 
possible it is compiledfrom 1758 upwards, but often a side issue 
takes the compiler on even into the present year. Every book 
when 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. 
2. Remarks on the Dentition of Snakes and on the Evolution 
of the Poison-fangs. By G. A. Boutenecsr, F.R.S. 
[Received May 26, 18.°° ] 
By the researches of Mr. G. 8. West on the buccal glands of 
Snakes, the results of which appeared in the last volume of these 
‘ 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 abandon’. 
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 figures 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- 
1 My views have been accepted by Prof. Cope, who, 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, z. ¢. that the Colubriform venomous 
Snakes, the Proteroglypha, do not differ in any fundamental respect from the 
non-venomous Colubridx.” 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 Boide, the most generalized of all Ophidians, between the 
Opisthoglypha and the Proteroglypha. 
