144 BULLETIN 188, tJNITED STATES NATIONAL MUSEUM 

 CYCLOCHEILICHTHYS ARMATUS (Cuvier and Valenciennes) 



Barbus armatus Cuvier and Valenciennes, 1842, vol. 16, p. 163 (Java). 

 CyclocheUichfhijs aitnatus Weeer and de Beaufort, 1916, vol. 3, p. 103 (Siam). — 

 Fowler, 1935a, p. 121 (Khao Nam Poo) ; 1937, p. 186 (Pitsanulok, Kemarat). 



In the East Indies this species is known from Java, Borneo, and 

 Sumatra. It is not abundant but it has a wide distribution in Thai- 

 land. The first specimen from local waters seems to have been one that 

 reached the British Museum from "Western Siam," collected by Bock. 

 This is the specimen on which Weber and de Beaufort based tneir 

 Siamese record. Other specimens have come from Central Thailand 

 (Paknampo, Khao Nam Poo, and Pitsanulok) ; from the Mekong at 

 Kemarat (Fowler) ; and from the Tale Noi, where it is common but 

 of small size (up to 11 cm.). 



In small examples (9.5 to 11 cm. long) the least depth of the caudal 

 peduncle is less than 0.5 length of head. The fish reaches a length of 

 23 cm., and large specimens have the depth of the caudal peduncle more 

 than half length of head. 



This species is most readily recognized by the single pair of short 

 maxillary barbels combined with 6.5 or 7 rows of scales above the lat- 

 eral line, 4 or 5 rows of scales between the lateral line and the base of 

 ventrals, and 15 to 18 branched rays in the pectoral fins, which extend 

 on the ventral base. 



Three additional specimens from the upper Nan River, April 19, 

 1930, the largest, 18 cm. long, the others about 15 cm. long, have the 

 bases of the scales of back and sides with a black crescentic spot which 

 is sharply contrasted. 



This species at Nan is known as pla pak Hem. 



CYCLOCHEILICHTHYS COOLIDGEI, new species 



Figure 19 



D'escHption. — Upper profile of head nearly straight, profile from 

 nape to dorsal fin slightly arched; depth 3 in standard length; least 

 depth of caudal peduncle 1.3 in its length and slightly more than 2 

 in head; head 4 in length; eye 3.5 in head, equal to snout and inter- 

 orbital space; maxillary reaching vertical from nostrils; maxillary 

 barbels less than 0.25 eye; gill rakers thick, fleshy, with obtuse ends, 

 1 + 5 on first arch. 



Squamation : Scales in lateral line 35, in transverse line from mid- 

 line of back to base of ventral fin 5.5-1-4.5, in predorsal region 13, cir- 

 cumpeduncular 18 ; well-developed scaly sheaths along the base of the 

 dorsal and anal fins. 



Fins : Dorsal origin over eleventh scale of lateral line, slightly behind 

 ventral origin, midway between tip of snout and last scale of lateral 

 line, dorsal rays iii, 8, last simple ray rather strong, finely serrated, and 



