1l4 
subject must be gathered from some old works, and this is scanty 
enough, as we shall see hereafter. And yet, what has been con- 
sidered down to the present day the scarcest and most remarkable 
species of Snake—Herpeton tentaculatum—proves now to be an in- 
habitant of this very country. A collection of reptiles, transmitted 
last year by M. Mouhot to the British Museum, contains two speci- 
mens of this Reptile, beautifully preserved in every respect, and also 
twenty-two other species. We thus gain a first step to a fuller 
knowledge of Siamese Herpetology. I proceed to give an account of 
this collection. 
1. Emys s1AMENsIs, Gray. 
2. CALOTES VERSICOLOR, Daud. 
3. GecKO vERUS, Merr. 
4, TiL1QUA RUFESCENS, Shaw. 
This species varies very much: the posterior frontals form a more 
or less broad suture together in some of the specimens, whilst in 
others they are entirely separated from each other by the intervening 
medial shield. The black lateral streak is most conspicuous in indi- 
viduals of middle age, and is gradually lost in older ones; it dis- 
appears entirely if the epidermis is stripped off. Young individuals 
are uniform blackish-ash, minutely speckled with whitish. 
5. XENOPELTIS UNICOLOR, Reinw. 
6. TYPHLOPS DIARDII. 
7. CALAMARIA QUADRIMACULATA, Dum. et Bibr. 
8. SIMOTES TRINOTATUS, Dum. et Bibr., var. 
Duméril states correctly the number of longitudinal series of scales, 
which is twenty-one. The Siamese specimen, however, differs in the 
coloration, having the belly pure white, the back reddish-olive, some 
scales being blackish, and forming transverse streaks in regular inter- 
spaces, but not three distinct series of spots. 
9. TRopIpONoTUS QuincuNctatTuS, Schleg. var. F., Gthr. 
10. HypstrHinA AiR, Wagl. Variety without series of spots on 
the belly or tail. 
11. HerPeTON TENTACULATUM, Lacép. (Pl. XXIII.) 
This Snake is hitherto known from a single discoloured specimen 
only, which has served for all the descriptions published. After the 
account and the figure given by Schlegel, it does not appear neces- 
sary to repeat a description of the form, or of the shields and scales, 
in which our specimens do not show any difference. The larger of 
