2 PEOCEBDINGS OP THE NATIONAL MUSEUM vol.72 



These distinctions, based as they were on a few specimens only, 

 and on characters easily shown to be too variable, did not recommend 

 themselves to contemporary herpetologists. 



A second attempt at subdivision was made by Guenther who called 

 attention to the existence of at least two forms. In fact, in his 

 Reptiles of British India (1864) he treated them as two distinct 

 species and gave figures to illustrate one of their structural differ- 

 ences. This according to him consisted in the presence of one or more 

 small scales between the supranasals in the form he called Tritnere- 

 surus gramdneus, while in the other, T. e^tythrurus, the supranasals 

 are in immediate contact with each other. In addition he mentioned 

 slight differences in coloration, underside pale greenish in the former, 

 greenish-white combined with whitish upper lip in the latter. Un- 

 fortunately, as he was unable to appreciate any correlation between 

 the specimens thus separated and their geographical distribution, he 

 applied two names, the types of which undoubtedly belong to the 

 same form. As a consequence Boulenger refused to recognize any 

 distinction, and united them again. 



Stoliczka, who collected both species and wrote four years after 

 Guenther, recognized the distinctness of the two forms and accepted 

 his nomenclature, but had apparently a better appreciation of their 

 geographic relations, as he refers the Burmese and Malay Peninsula 

 specimens to the so-called T. erythrurus and restricts the other form 

 to the Khasi Hills and Assam. At the same time he casts doubt 

 upon its being found in the interior of the northwestern Himalayas 

 and especially the alleged occurrence in Ladak. 



Accepting the above, including Guenther's erroneous nomenclature, 

 Anderson ^ discussed the question of the distinction between the two 

 forms in still greater detail. He i-ecorded as T. gramineiis several 

 specimens from Ponsee, western Yunnan, one of which had 23 scale 

 rows, while he listed the so-called T. erythrwnis as from Upper 

 Burma. In describing the distinguishing characters, however, he 

 came to the conclusion that they are subject to considerable variation, 

 but that the majority of the specimens conform to the accepted 

 diagnoses. 



Doctor Mell - also had an opportunity to study both forms in the 

 field and observed certain differences in structure and coloration 

 between specimens from the northern mountainous region of Kwan- 

 tung and those from the southern lower regions of the same Province. 

 Unfortunately, he also adhered to Guenther's application of the name 

 graminetis to the northern subspecies. His choice of name for the 

 southern form, which he calls Lachesis grarnivneus alholabris (Gray, 



1 Zool. Res. Exped. West Yunnan, 1879, pp. 828-832. 



2 Arch. Naturg.. vol. 88, sec. A, pt. 10, 1922, pp. 126-128. 



