564 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



latter was described from the lower Menam Chao Phya. The ap- 

 parent differentiating characters are as follows : 



la. Dorsal fins described and figured as entirely separated ; head scaled above 

 posterior to eyes and on oi)ercle and preopercle; scales in longitudinal 

 series 70 to 90; first dorsal fin with dark longitudinal bars cantoris 



lb. Dorsal fins completely united by a membrane; head naked; scales in longi- 

 tudinal series about 55 ; first dorsal fin without bars livingstoni 



APOCRYPTICHTHYS CANTORIS Day 



Apocryptichthys cantoris Day, 1876, vol. 1, p. 302, pi. 57, fig. 7 (Madras, Anda- 

 mans).— Smith, 1931d, p. 189 (Gulf of Siam off the Meklong). 



Described from the east coast of India and the Andaman Islands, 

 this fish was first discovered in other waters in 1923 when three speci- 

 mens, 7.5 to 8.3 cm. long, were taken in a shore seine in the Gulf of 

 Siam near the mouth of the Meklong when a large volume of fresh 

 water was pouring into the gulf. 



Although Day described the fish as having the head scaleless, Kou- 

 mans (1931), having examined Day's type, determined that it had 

 scales on the top of the head posterior to the eyes and also on the 

 opercles and preopercles. Day furthermore described and figured the 

 dorsal fins as entirely separated, but whether this was a natural fea- 

 ture or was due to mutilation is not known definitely; in the other 

 species herein listed and in Herre's new species from China the dorsal 

 fins are united by a membrane having the full depth of the adjoining 

 rays. 



APOCRYPTICHTHYS UVINGSTONI Fowler 



Apocryptichthys Uvinffstowi Fowler, 1935a, p. 162, figs. 131, 132 (Paknam). 



This fish is known from three specimens, 9.3 and 9.4 cm. long, taken 

 in the Menam Chao Phya at Paknam. It was separated specifically 

 from A. cantoris by having the dorsal fins fully united, only about 53 

 or 54 scales in longitudinal series, and different coloration of the dorsal 

 and caudal fins. The enumeration of the scales in the longitudinal 

 series, however, did not take into account the large number of small 

 or rudimentary scales anteriorly, which scales were counted by Day 

 in his description of cantoris. Other apparent differences — squama- 

 tion of the head, coloration of fins, and similar characters — may jus- 

 tify the retention of this species pending the examination of further 

 material than is now available. 



Genus BOLEOPHTHALMUS Cuvier and Valenciennes 



Boleophthalnius Cuvieb and Valenciennes, Histoire naturelle des poissons, vol. 

 12, p. 198, 1837. (Type, Boleophthalmus hoddaerti (Cuvier and Valen- 

 ciennes) = Go &ms boddarti Pallas.) 



