FRESH-WATER FISHES OF STAM, OR THAILAND 549 



CTENOGOBIUS VEXILLIFER (Fowler) 



CtenogoMus vexilUfer Fowler, 1C37, p. 252, fig. 282 (Bangkok). 



Known from a single specimen, 4.8 cm. long, from Bangkok, this 

 species has about 27 scales in longitudinal series, 10 minute predorsal 

 scales, very conspicuous rows of papillae on the opercles and cheeks, 

 several dorsal spines prolonged, and strongly contrasting coloration 

 especially of head and fins; body brown, with irrejznlar blackish- 

 brown blotches on back and sides; head with 5 blackish bars under 

 eye and on preopercle and opercle; lower two-thirds of second dorsal 

 blackish brown, margin pale; caudal with 5 or 6 narroAv wavy 

 blackish-brown cross stripes and several round white spots at base; 

 anal membranes black; ventrals grayish black with white margin; 

 and pectorals gray, with 2 irregular black basal spots extending on 

 the white fleshy base. 



Genus BRACHYGOBIUS Bleeker 



BrachygoMus Bleekee (453), Arch. N^erl. Sci. Nat., vol. 9, p. 315, 1874. (Type, 

 Oobius doriac Giinther.) 



BRACHYGOBIUS SUA (H. M. Smith) 



Thaigobiella sua Smith, 1931a, p. 35, fig. 17 (Bangkok). 



BrachygoMus xanthosona Fowler, 1937, p. 248, figs. 263-277 (Bangkok). (Not 

 Oobius xanthosona Bleeker.) 



BrachygoMus xanthom^elas Herre, in Herre and Myers, 1937, p. 43, pi. 4 (Singa- 

 pore and Johore, Malaya). 



This fish has been known from Thailand only in canals and tidal 

 ditches in the city of Bangkok. It appears at times in small scattered 

 schools at the surface of the turbid water, where it is recognizable, 

 notwithstanding its small size, by black cross bands on the creamy 

 yellow background of the body. Specimens were collected in January, 

 May, and August, that is, during both the dry and the rainy seasons. 



This is one of the most diminutive of the local gobies. It appears to 

 reach full maturity when only 2.7 to 2.8 cm. long. Fish 2 cm. long, 

 taken in May, were females fully distended with eggs. 



A fish kept in a small glass jar in Bangkok for a period of six weeks 

 never overcame its shyness, and remained on the bottom concealed 

 among particles of sticky mud or beneath the fibrous roots of a natant 

 water plant. 



The original description of the species, from a single specimen 2.7- 

 cm. long, gave only 5 rays in the first dorsal fin. The type is not now 

 available, but from various other specimens in hand it would appear 

 that either an error was made in counting the dorsal spines or that the 



590087—45 36 



