Following the world famous "Catalogue of Snakes of the British 

 Museum of Natural History," by Boulenger (1896), all modern 

 herpetologists regard the species of poisonous snakes described from 

 Southeast Asia by Boie (1827) under the name Trigonocephalus 

 rhodostoma [as belonging] to the genus Ancistrodon Beauv. Actually, 

 according to its external characteristics, this species in general 

 answers the diagnosis (strictly speaking, based only on external 

 morphology) of the genus Ancistrodon . However, in contrast to the latter, 

 the scales of this species are absolutely smooth, without keels. In 1853 

 Dumeril gave attention to this detail, which warranted placing this 

 species in the monotypic genus Leiolepis (from the Greek words meaning 

 "smooth" and "scales"). Earlier, hoVever, Cuvier (1829) had described a 

 genus of lizards of the family Agamidae under the very same generic name, 

 which is still used today. No other external morphological differences 

 from Ancistrodon are found in this snake. As a consequence, Boulenger 

 placed the generic name of this species of pit viper in synonymy with the 

 genus Ancistrodon . On the other hand, one must note its significant 

 biological peculiarities, which, so far as I know, do not occur in all 

 the other species of this genus. Thus, A. rhodostoma exhibits oviparity, 

 not viviparity, depositing 13-30 eggs, which the female protects during 

 the entire period of incubation, lasting 42-47 days. 



In connection with the treatment for "The Fauna of the U.S.S.R." of 

 the genus Ancistrodon , specimens of which occur in the Soviet Union, I 

 prepared and made a careful study of the skulls of a number of species 

 of this genus, including A. rhodostoma . As the comparison of skulls of 

 Nearctic species [a. piscivorus (Lacep. ) and A- mocasen (Beauv.)] with 

 skulls of three Palearctic species [a. halys (Pall.), A. blomhof f i (Boie) 

 and A- strauchi Bedr. ] showed, there are few significant differences among 

 them. [p. 791 ] The skulls' are very similar to each other and differ 

 mainly in some details of structure of the palatine bone, in particular its 

 shape, the number of fixed teeth, and by the insertion of the caudal end of 

 the transverse [ectopterygoid ] bone into the pterygoid. In other words, 

 the Palearctic and Nearctic species undoubtedly exhibit close relationships 

 to one another within the genus Ancistrodon . 



A completely different situation exists in the skull of A- rhodostoma - 

 the species which is rather common in the southeastern part of outer 

 Palearctic Asia, is widespread on the peninsulas of Indo-China and Malacca 

 and is also on the Greater Sunda Islands. Even with a superficial glance 

 at the skull of this species, it is easy to observe the very broad intra- 

 orbital space, formed by the frontal bones; also, there is a significantly 

 greater breadth of skull in the parietal region, that makes the general 

 appearance of the skull from above similar to that of some other genera of 

 rattlesnakes, for example Crotalus and Sistrurus. 



