178 Records of the Indian Museum. Wor. VEE 
are naturally different we can find no structural difference. We 
have now no doubt that the specimens are specifically identical. 
Family COBITIDAE. 
The Loaches, which share with the Trout Carp (Schizothora- 
cinae) the waters of the Central Asiatic plateau, are represented in 
those of Seistan by two genera, both of which also occur in 
Central Asia. One of these genera, Nemachilus, has a wide range 
in the Palaearctic and Oriental regions. Its single representative 
in Seistan is apparently dimorphic and occurs also in the head- 
waters of all the rivers immediately north and east of the great 
Himalayan range and the Hindu Kush. This species is N. stoli- 
czkae (Steind.), of which we regard N. stenurus, Herz. as a dimorph. 
Apart from Seistan, N. stoliczkae is found only at high altitudes. 
The other Cobitid genus that occurs in Seistan is here des- 
cribed as new. It is closely related in structure to Nemachilus 
but possesses one peculiarity, a soft dorsal fin, which differentiates 
it from most other Cyprinoidea and, together with its peculiar facies, 
constitutes it an apparent link between the Cobitidae and the 
Siluroidea. We discuss the structure, function and homology of 
this fin below. The genus, though strangely enough the soft fin 
has not been recognized as such hitherto, occurs also in Turkestan, 
and it is possible that Persian species assigned by Nikolsky to 
Nemachilus may also belong to it. ‘he new genus is represented 
in Seistan by two species. 
Genus Nemachilus, v. Hasselt. 
The one Seistani species (N. stoliczkae) of this genus belongs 
to alittle group of Central Asiatic forms in which the Tibetan 
N. lhasae, Regan, and N. yarkandensis, Day, from Turkestan 
must also be included. This group is distinguished by the elongate 
form of the body and especially by that of the caudal peduncle. 
The fins are large, the eyes small, and scales are as a rule absent. 
The ventral surface is rounded and not specially adapted for 
purposes of adhesion. These fish are inhabitants of rapid but 
turbid streams, as a tule at very high altitudes. We have 
unfortunately no information as to the circumstances in which the 
Seistan form occurs. 
Nemachilus stoliczkae (Steindachner). 
1866. Corbitis stoliczkae, Steindachner, Verh. Zool. bot. Ges. Wein., 
XVI, p. 793; pl. xiv, fig. 2. 
1878. Nemachilus stoliczkae, Day, Fishes of India, II, p. 620, pl. cly, 
fig. 10. 
1888. Men asuiten stoliczkae, Herzenstein, op. cit., p. 14, pl. 1, figs. 2-5 ; 
pl. iii, figs. 1-4; pl. vii, figs. 3-4; pl. vill, fig. 12. 
1888. Nemachilus stenurus, id., op.cit., p. 64, pl. 1, fig. 1. 
1906. Nemachilus stenurus, editorial note to Regan, Four. As. Soc. 
Bengal, il, p. 8. 
1908. Nemachilus stolicskae, Lloyd (in part), Rec. Ind. Mus., \1, p. 341. 
