94 



BXJLLETIN 188, UNITED STATES NATIONAL MUSEUM 



scales surrounding the narrowest part of the caudal peduncle (always 

 12) . The branched rays in the dorsal fin are always 8. The branched 

 rays in the anal fin number 8 to 12, with 11 or 12 predominating. The 

 pectoral rays are i, 10 or i, 11. The variational frequency of some of 

 these features is shown in the following tabulation covering 13 speci- 

 mens from Thailand and 8 from French Indo-China near the Thailand 

 border : 



Coloration (in preservative) : Upper half of body and head light 

 green, the scales ^"vith darker edges; belly white; under side of head 

 silvery; seven black quadrate spots along side before dorsal fin, the 

 line of spots being continued backward as a narrow black stripe to a 

 point over midbase of anal fin ; posterior half of median line of body 

 with a black band, which is less distinct anteriorly but broadens and 

 becomes jet black on caudal peduncle, this band being separated from 

 the color of the back by a narrow pale yellow stripe, above which is a 

 narrow, indistinct blackish stripe ; dorsal anteriorly with a white edge, 

 otherwise dusky ; caudal and anal fins dusky ; ventrals and pectorals 

 partly dusky. 



The highest development of the coloration — with a series of blackish 

 quadrate blotches along the side anteriorly and a black lateral band 

 posteriorly, becoming wider toward the base of the caudal fin — occurs 

 in both sexes. Sexual maturity and ripening of the eggs, however, may 

 not necessarily be associated with the greatest development of the 

 black markings : thus, five of the specimens from Huey Nam Puat, 6.7, 

 6.8, 6,8, 7.1, and 7.8 cm. long, all approaching the spawning period, 



