FRESH-WATER FISHES OF SIAM, OR THAILAND 559 



of an adult of P. phya. * * * One of us watched a large individual re- 

 pairing its rampart, which had been injured by the tide, for some time, but 

 could not be sure exactly how this was accomplished ; the fish certainly went 

 down the central hole and returned in a few seconds, bringing a pellet of mud 

 with it. 



The eyesight of this species appears to be keen, both in air and water, and to 

 range in the former element for a radius of at least thirty feeL We noticed re- 

 13eatedly that when we had frightened an individual into its burrow, it remained 

 concealed as long as we stayed still, but reappeared as soon as we began to move 

 away ; and this would seem to indicate that the fish could see from beneath the 

 surface of the water what was going on in the air. On land, at any rate, it is 

 absolutely deaf, and Robinson found, when shooting specimens, that those which 

 were not hit took no notice whatsoever of the report of the gun, and only moved 

 when the shot spattered them with mud. 



The fish called Periopht?ialmus 'phya^ described by Johnstone ( 1903) 

 from the Patani River in the Peninsula and the Jambu River in 

 Malaya, seems to be the present species. Johnstone observed that it 

 "resembles P. schlosseri^ but appears to differ in (1) the complete 

 fusion of the pelvic fins in both young and adult specimens; (2) the 

 number of rays in the pectoral fins; (3) the number of rays in the 

 caudal fin, and (4) the larger size of the specimens obtained." The 

 size at which the ventral fins become completely joined together 

 varies with individuals and can hardly be regarded as of specific sig- 

 nificance, although it should be stated that the three specimens, 2 to 2l^ 

 inches long, in which Johnstone found the ventrals completely fused 

 are smaller than any that have been found by the present writer to 

 possess this feature. Ordinarily the complete union of the innermost 

 rays by a membrane may not be expected under 12 cm. (4.50 to 4.75 

 mches), and the smallest specimen in the U. S. National Museum in 

 which the ventrals are fully joined by their inner edges is 12.5 cm. 

 long, including caudal fin. As regards pectoral rays, specified as 16 

 to 18 in P. phya^ this number does not seem unusual in P. scKLosseH; 

 specimens in a lot of the latter from Borneo in the National collection 

 have 17 pectoral rays. Likewise, the number of caudal rays in phya^ 

 namely 17 to 23, is matched by 18 to 20 rays in Bornean specimens of 

 typical schlossen. 



The colloquial name for this fish in Thailand is pla tin. A name 

 heard on the Menam Chao Phya below Bangkok is pla kajcmg. 



Family APOCRYPTEIDAE : Apocrypteid Gobies 



The genera herein placed in this family group have been variously 

 classified and allocated by authors. Bleeker (1874 [453] ) placed them 

 in a phalanx (Apocrypteini) of his subfamily Gobiiformes and divided 

 them into two subphalanges, one (Apocryptei) containing Apocryp- 



