no 



BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



' This is the largest of the local rasborids. For the Indo-Australian 

 Archipelago a length of 17 cm. is reported ; for Thailand the largest 

 secured are about the same. The females average larger than the 

 males. 



Specimens from Thailand labeled Rasbora dusonensis obtained 

 from the Paris Museum are in the British Museum. Giinther and 

 Weber and de Beaufort considered R. dusonensis a synonym of R. 

 argyrotaenia. 



V%'' 



f v<^ ■^ 



ii^44 





Figure 11. — Rasbora argyrotaenia (Bleeker). Drawn by Nai Chote Suvatti; courtesy of the 



Thailand Government. 



Although Hora (1923b) identified as R. argyrotaenia two young 

 specimens collected by Dr. Malcolm Smith in a waterfall stream on 

 Koh Chang, the writer's own very extensive collecting in the streams 

 of that island yielded only R. lateristriata. 



The common name for this fish throughout Thailand is pla slew. 



RASBORA RETRODORSALIS, new species 



Figure 12 



Description. — Depth 3.6 in standard length; least depth of caudal 

 peduncle 1.5 in its length and 0.5 depth of body ; head 4.5 in standard 

 length ; eye equal to snout, about 3.5 in head, 1.5 in interorbital space ; 

 mouth very oblique, its anterior end on level with upper edge of pupil, 

 its posterior angle reaching 0.5 distance from tip of snout to eye ; sym- 

 physeal hook on lower jaw well developed and fitting into a deep notch 

 on upper jaw. 



Squamation : Scales in lateral line 34, in transverse line from middle 

 of back to base of ventral fin 4.5-1-1, in predorsal region 14, around 

 caudal peduncle 16, with 9 rows of scales between the lateral lines 

 counted over the back. 



Fins: Dorsal rays ii, 7, longest less than head, origin of fin over 

 middle of a line from posterior margin of eye to terminal tube-bearing 

 scales of lateral line and over fourteenth scale of lateral line ; caudal 



