268 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



Fins: Dorsal rays, ii,8; anterior rays elongated, giving fin a some- 

 what falcate appearance, longest rays equal to head ; origin of dorsal 

 fin in advance of ventrals, much nearer to tip of snout than to base 

 of caudal fin, over tenth scale of lateral line; caudal longer than head, 

 deeply forked lobes pointed, upper lobe longer; anal falcate, rays 

 ii,5, longest 0.75 head ; ventrals i,8, broad, 0.8 head ; pectorals, i,14, as 

 long as head. 



Coloration : General color golden brown, silvery white below ; top 

 of head pale green ; numerous scales on back and on side nearly as low 

 as base of ventrals wath a black basal spot, these spots along lateral 

 line having a tendency to form a band posteriorly ; all fins pale yellow- 

 isli green, some of the dorsal rays and membranes dusky. 



Figure 53. Epaheorhynchos stigmaeus, new species: Type (U,S.N.M, No. 109765). 

 Drawn by Mrs. Alice. C. Mullen. 



Type and paratype.— The type (U.S.N.M. No. 109765), 12.5 cm. 

 long, and a paratype (U.S.N.M. No. 109763) and only other specimen 

 available, 11.4 cm. long, were taken February 2, 1932, in the Mekhan, a 

 tributary of the Meping, Northern Thailand. 



Remarks. — The Mekhan at the point where this species was found 

 is a clear cool stream flowing swiftly over gravel and shelving rocks. 

 Other fishes inhabiting the same stretch of river were Grossocheilus 

 sp. and Gyrinocheilus sp. 



The dermal flanges on the dorsal rays, found in various genera and 

 many species of Thai mountain-stream fishes, are very well developed 

 in this species. 



The relations of this species to the other members of the genus are 

 shown in the preceding key. The closest resemblance is to E. coatesi 

 in which there is a large, well-defined round black spot on the caudal 

 peduncle, as distinguished from the numerous irregular black flecks 

 on the back and sides in E. stigmaeus. The caudal peduncle in E. 

 coatesi is relatively wider and has 16 scales around its narrowest part, 

 as compared with 14 in stigmaeus, and there are various minor features 

 in which the two forms differ. 



