FRESH-WATER FISHES OF SlAM, OR THAILAND 



91 



In the Southeastern district it is very common in Nong Khor and 

 has been collected in a small tributary of the Krat River on Kao 

 Seming and in rivulets on Kao Sabap. 



The species shows considerable variation within certain limits. 

 Thus, the maxillary barbel may extend only to the base of the ventral 

 fins in some specimens, to the ventral opening in others, and to or 

 beyond the base of the anal fin in others; and the lateral line, which 

 does not usually continue as far as the base of the anal fin and may 

 not reach the base of the ventrals, in a specimen 7.1 cm. long from 

 the Menam Chao Phya, at Paknam, terminated on one side on a scale 

 above the origin of the anal fin and on the other side above the base 

 of the ventrals ; in a female T.2 cm. long from the Menam Chao Phya 

 at Paknam it terminated on one side on a scale above the origin of 



Figure S. — Esomus metallicus Ahl. Drawn by Luang Masya; courtesy 

 of the Thailand Government. 



the anal fin and on the other side above the base of the ventrals ; and 

 in a female 7.2 cm. long, with ripe eggs, taken in a ditch in Bangkok 

 May 26, 1925, there was no lateral line on either side. The black 

 lateral stripe is usually quite distinct, extending from behind the eye 

 to the base of the caudal fin, but it may be indistinct anteriorly, 

 o ' This is one of the most abundant of the small cyprinid fis.ies. Its 

 favorite haunts are weedy ditches and drains connected with large 

 streams. It makes an excellent aquarium fish, easily adapted to con- 

 finement in small vessels and remaining active and hardy on a diet 

 of mosquito larvae and small crustaceans. 



The fish has received no special vernacular name and is apparently 

 not distinguished by fishermen from other small cyprinids. 



DANIOPS, new genus 



Similar to Danio in having a complete lateral line, but differs in 

 having a reduced number of branched dorsal rays, a shelf extending 

 backward from the lachrymal bone, and pharyngeal teeth in two rows. 



