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Show 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, &c. 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 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. B O U L E N G E R , F.R.S. [Eeceived May 26, 1896.] By the researches of Mr. G. S. 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, hi 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 M y 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, i. e. that the Colubriform venomous Snakes the Proteroglypha, do not differ in any fundamental respect from the non-venomous Colubrida?." Dr. Giinther (Biol. C.-Am., Eept. 1895), on the other hand, etill adheres to the old arrangement, as evinced by his continuing to intercalate the Boidse, the most generalized of all Ophidians, between the OpUthoglypha and the Proteroglypha. - |