FRESH-WATER FISHES OF SIAM, OR THAILAND 269 



Genus CROSSOCHEILUS van Hasselt 



Crossocheilus van Hasselt, Alg. Konst. Letterbode, vol. 2, p. 132, 1823. (Type, 

 Crossocheilus ohJongus van Hasselt.) 



In this genus of small fishes of the Indo-Australian Archipelago 

 and southern Asia, the principal characters are the continuation of 

 the skin of the rostrum as the upper lip, the nonjunction of the upper 

 and lower lips, the connection of the upper lip with the lower jaw 

 by a frenum, the presence of a pair of rostral or maxillary barbels 

 (in Thai species), and the dorsal fin with eight branched rays and 

 the last simple ray nonosseous. 



One species has been known from Thailand from an early date 

 from the collection of Mouhot. Another was added by the writer in 

 1928. More recently Fowler has described several other species from 

 Thailand waters. The species of Crossocheilus may be differentiated 

 as follows: 



la. Tveo rostral and 2 maxillary barbels. 

 2a. Upper lip fringed or plaited ; 2 rostral barbels. 

 3a» Depth 4.5 to 5 ; a dark longitudinal band from head to caudal fin ; no 



black bar behind gill opening oblongus 



3&. Depth 3.8 to 4.25 ; a black bar behind gill opening. 



4a. A blackish longitudinal band on posterior part of body, this expanding 



into an elongated blotch on caudal peduncle tchangi 



4&. No black longitudinal band on body ; scales of back and sides edged 

 with dark brown, forming a network ; a black blotch entirely across 



caudal peduncle at base of caudal fin reticulatus 



2b. Upper lip entire. 



5a. Two rostral barbels ; scales in lateral line 35 to 38 ; body marked by 

 numerous longitudinal dark lines following the rows of scales; 



fins plain reba 



56. Two maxillary barbels ; scales in lateral line 34 or 35 ; body without 

 longitudinal dark lines ; dorsal fin with a broad black median band 

 and a narrow dark edge, caudal fin with small scattered brown spots 



on each lobe caudiguttatus 



16. Only 2 barbels, either rostral or maxillary ; a broad silvery lateral band 

 through which there may run a dark streak ; a round black spot at end of 

 lateral line on both caudal peduncle and caudal fin cobitis 



CROSSOCHEILUS OBLONGUS (Cuvier and Valenciennes) 



Labeo oblongus Cu\ieb and Valenciennes, 1842, vol. 16, p. 357 (.Java). 

 Crossochilns oUongus Smith, I931d, p. 187 (Jadi). 



This species, known from Java, Borneo, Sumatra, and Malaya, 

 was added to the Thailand fauna in 1928 when a specimen 10.8 cm. 

 long was taken in Tadi Stream, west of the town of Nakon Sritamarat, 

 Peninsular Thailand. This example was typical. The fish must be 

 very rare in local waters. 



In the East Indies a length of 16 cm. is attained. 



