212 MAJOR F. WALL, I.M.S., C.M.Z.S. 
that,the posterior maxillary teeth are grooved, and it exactly accords with specimens 
of spiralis (vel brugmansit) except in the lower number of neck scales. ‘These in the 
two museum specimens of melanocephalus are 25 and 24, but in the nine I specially 
A B 
Fig. 21.—Distira melanocephala, x 2. 
examined in Japan they ranged from 23 to 27, the latter number being already 
recorded for spiralis. It is, therefore, impossible to draw a dividing line between the 
two species, and I take the view that melanocephalus is a local variety of spiralis 
characterised by rather fewer neck scales. 
melanosoma ({Giinther).—This is only known from a single specimen in the 
British Museum which I cannot see differs in any way trom spiralis, vel brugmansit, 
except in colour. The sole distinction between the two utilised by Mr. Boulenger 
in his key (p. 287) is that the posterior chin shields are in contact in brugmansit, 
separated in melanosoma. His detailed descriptions of the scale characters in each 
show complete accord in every other particular, nor can I, by careful examination of 
the specimens side by side, find any differences between them. As regards the chin 
A B G 
Fig. 22.—Distiva melanosoma. After Ginther, Rept. Brit. Ind., pl. xxv, fig. E. 
shields, they are variously separated or in contact in many species, and are separated 
in at least three others of the large series of spiralis examined by me. ‘The colour is 
certainly peculiar, in that the black bands are unusually broad, and melanosoma might, 
I think, be conceded the rank of a colour-variety, characterised by the breadth of its 
annuli. The postocular is single, as correctly stated in Mr. Boulenger’s description 
(p. 291), not two as incorrectly given in his key (p. 287). 
longiceps (Gunther).—This is known from a single specimen in the British Mu- 
seum in which I find the post-maxillary teeth are grooved. Its affinities are extremely 
close to both spiralis and cyanocincta, in fact it combines the distinguishing charac- 
ters of both these forms so intimately that it is difficult to decide to which to refer it. 
I incline to the opinion that it should rank with sAzralis on account of the costals in 
