8 SECOND YARKAND MISSION. 



I have not overlooked the fact mentioned by Dr. Giinther in the "Reptiles of British. 

 India," ' and to which reference has already heen made, that specimens from Tibet had been 

 compared by Professor Peters of Berlin with typical examples of L. caudivolvula, and found 

 specifically identical. I confess that it appears at the first glance as if the opinion of so high 

 an authority on the Keptilia as Professor Peters must be more correct than mine, but I think 

 there must be some mistake, as I have already indicated when noticing the description of 

 P. caudivolvulus by Dumeril and Bibron. The original types of Pallas can scarcely be in 

 Berlin, and it has frequently happened that other species have been sent from Russia under 

 Pallas' names. Under any circumstances I cannot but think, for the reasons given above, that 

 Pallas must have described a different lizard. 



Steindachner in his description of P. stoliczJcce, which is certainly the same lizard as 

 P. theobaldi, several of the specimens examined by Steindachner being from the typical 

 locality of the last-named species, points out that P. stoliczkce differs from P. caudivolvulus 

 in its shorter tail and in having smooth scales on the upper surface of the limbs. The latter 

 character, however, is not constant. Keels may generally be detected in P. theobaldi on the 

 scales of the tarsus, and not unfrequently on the thigh and forearm, and in the Turkestan 

 variety, P. forsythi, they are the rule. The length of the tail is, however, a characteristic 

 distinction, though, I believe, it is not the only one. 



It is only after long and repeated comparison that I have come to the conclusion, that 

 P. forsythi of Anderson cannot be separated from P. theobaldi? At the first glance, 

 they appear distinguished by colour and by the Turkestan form having some scattered, whitish, 

 enlarged scales on the back, and keels on the scales covering the upper surface of the limbs. 

 Individuals, however, vary greatly in the scales of the back ; in some these are convex and 

 granular, in others flat, smooth, and even subimbricate ; in some larger in the middle of the 

 back, in others nearly the same size throughout. The scales on the top of the head are 

 scarcely alike in any two individuals ; some have the scales large on the occiput and very 

 small on the supra-orbital region, in others all are of about equal size ; in some the enlarged 

 superciliary scales almost reach the nasals, in others three or four small scales intervene. 

 The keels on the limb scales and the enlarged scales on the sides of the back are no more 

 constant than the other characters. I find specimens from Western Tibet with a few 

 scattered enlarged scales, and with distinct keels on the limb-scales, and I find specimens from 

 Eastern Turkestan in which the enlarged scales are wanting and the keels can scarcely 

 be detected. 



Even in colouration, I do not think the difference, although it is usually marked, is 

 constant. P. forsythi has almost always a row of rather distant dark spots, arranged in pairs 

 down each side of the back. These spots consist of rather pointed scales. P. theobaldi 

 varies exceedingly in colour. Some specimens, perhaps the most, are rather irregularly 

 spotted, others have large ocelli on the back ; in others again there are no markings whatever. 

 But there is very often a tendency to a double row of spots down the back, and in some 

 cases a very near approach to the colouration of P. forsythi, and in the latter the spots 



1 p. 161. 



3 I may here remark that I believe Dr. Anderson was misled by his collectors into supposing that the specimens of P. theobaldi 

 described by him, Proc. Zool. Soc., 1872, p. 387, under the name of P. caudivolvulus, were from 'Yarkand. Like the gecko named by 

 him Cyrtodaciylus yarkanAensis, I think it almost certain that the Phrynocephali in question must have been collected in the 

 Upper Indus valley, in Ladak. Every specimen from Yarkand and Eastern Turkestan in Dr. Stoliczka's large collection has the 

 colouration of P. fcrsythi, whilst the specimens described by Dr. Anderson, which I have examined, are uudistinguishable from 

 some of those procured by Dr. Stoliczka in Ladak. 



