THE FAUNA OF A DESERT TRACT IN SOUTHERN INDIA. 189 



Calotes gigas. 



C. versicolor (partim), Annandale in J our v. As. Soc. Bengal, 1905, p. 87. 



In spite of what I said in the paper referred to regarding Blyth's Calotes gigas, I think 

 that it will be well to regard this form as having conventional specific rank. It is evidently 

 no more than a race (probably local) of C. versicolor; but as it does not appear to have been 

 customary to recognize subspecies in the genus, it will be convenient to call it by 

 Blyth's name pure and simple. When I published the note alluded to I had examined a 

 large series of specimens, none of which were in good condition ; but the examination of 

 a considerable number of living and freshly-killed examples, both of C. versicolor and of 

 C. gigas, shows that sufficient attention was not paid to certain characters which are 

 obscure in badly-preserved material and can only be detected in such material when 

 carefully sought for. The only objection to regarding the two forms as distinct species is 

 the difficulty of diagnosing the females, for as regards the males, at any rate when they 

 are adult or at least half grown, there is no such difficulty. 



In both sexes the number of scales round the body, their arrangement and general 

 character are practically identical in the two forms ; but in almost all cases it is quite easy 

 to separate one from from the other on inspection. In C. gigas (both sexes) the scales of 

 the body and limbs are distinctly larger, the body being relatively deeper than in C. ver- 

 sicolor ; those which form the crest differ in outline, their posterior edge in C. gigas being 

 more or less sinuous and their anterior edge convex forwards, while in C. versicolor both 

 edges are nearly straight ; in the former species, too, they are considerably longer than 

 in the latter, while the scales adjacent to them on either side have a more pronounced 

 character, their dorsal extremity being prolonged into a spine continuous with their 

 strong keel. The extent of the crest backwards is also greater in C. gigas (both sexes) 

 than in C, versicolor, and the cheeks are more swollen. The males of C. gigas have one 

 very characteristic feature, which is apparent even in half-grown individuals : — the 

 base of the tail is swollen and its dorsal and lateral surfaces are covered with scales 

 the edges of which are greatly thickened and plicated, the keel also being thickened 

 but barely extending to the edge of the scale posteriorly ; while the last three spines of 

 the crest are much thickened laterally. The coloration of the two forms is also slightly 

 different, and C. gigas perhaps does not possess the same powers of colour-change as 

 C. versicolor. The males of the former are (both in spirit and during life) of a sandy 

 colour, which may deepen into yellow on the swelling at the base of the tail The base 

 of many of the scales on the back and sides is densely irrorated with chestnut atoms, 

 and there may be dark transverse bars and reticulations on the sides. The greater part 

 of the thigh is frequently black or very dark-brown, and the whole of the hind-quarters 

 is generally darker than the fore-quarters. There are usually two conspicuous black 

 spots on the top of the head just behind the occipital scale, which may be white, and 

 more or less marked dark streaks radiate from the eyes. The female is far more boldly 

 marked. The ground colour of the dorsal surface of the body and limbs is a pale 

 chestnut, on which there is a very bold reticulation of sandy colour. The streaks 

 radiating from the eye are more conspicuous than in the other sex ; the two dark spots 



