1922.] S. L. Hora : Central Asiatic Cobitidae 77 



Nemachilus tenuis Day. 



1876. Nemachilus tenuis, Day. Proc. Zool . Soc. London, p. 796. 

 1878. Nemachilus tenuis, Day, Sci. Res. >nd York and Mission, Ich- 



thyol., p. 15, pt. v, fig. 4. 

 1898. Nemachilus tennis, Alcock, Rep. Nat. Hist. Res. Pamir Bound. 



Comm., p. 14. 

 1906. Nemachilus stenurtis, editorial note to Regan, Journ. As. Soc. 



Bengal, II. p. 8. 

 1920. Nemachilus stolicekae, Annandale and Hora (in part), Rec. hid. 



Mus. XVIII, p. 178. 



The specimens from which Day drew up his description of 

 Nemachilus, tenuis, came from two sources, from "Aktash. where 

 the waters of the Ak-su Pass to the Oxus " and from " Yankihissar, 

 where the rivers go to the Yarkand River." Day's specimens 

 from the latter locality are not to be found in our collection, 

 though there are several specimens of other species of the genus 

 from the same place The record, therefore, requires confirmation 

 as I think it improbable that the species really extends to the 

 Tarim river-system. Several specimens from the Great Pamir, 

 whence the waters pass to the Oxus system, were correctly referred 

 to this species by Alcock. 



Quite recently Annandale and I {op. cit.) identified the 

 Seistan examples as A7. stoliczkac, but I now believe that they 

 represent N. tenuis. The Seistan specimens were collected in the 

 Helmand River which may once have formed a part of the once- 

 extensive Oxus system. Regan (op. cit.) referred these specimens 

 to A/, stenurus on account of their long and narrow caudal peduncle, 

 but this is also a character of N. tenuis. The two species differ in 

 the following points : — 



N. stenurus Herz. N. tenuis Day 



The commencement of the dorsal fin is 

 nearer to the tip of the snout than to 



the base of the caudal fin. 

 The lower lip is continuous and entire. 



The commencement of dorsal fin is 

 either equidistant from the base of 

 the caudal fin and the tip of the snout 

 or it is slightly nearer to the former 

 than to the latter. 

 The lower lip is widely interrupted in 

 the middle and is greatly pliated. 



A7. stenurus was described from Dy-tschu, the sources of the 

 Yang-tse-kiang River ; while N . tenuis is known from the Oxus 

 system. 



Vinciguerra ' on the authority cf Regan referred his examples 

 from Skardu in the Indus System to N. stenurus for he writes, 

 " nel riferire questi individui al N. stenurus sono confortato dall' 

 avviso di Tate Regan, al quale li he comunicati." The specimens 

 require re-examination. 



It is evident from the above discussion that the character of 

 a long and narrow caudal peduncle is shared by a number of 

 species. Such species are N. stenurus from the sources of the 

 Yang-tse-kiang, N. tenuis from the Oxus system and N. lhasae 



1 Yinciguera, Ann. Mus. Stor. Nat. Genova XI. VII, p. 148 (1916). 



