FRESH-WATER FISHES OP SIAM, OR THAILAND 565 



The availability of the name Boleophthalrrms is in some doubt. It 

 may have to be suppressed as a synonym of Apocryptes. For the pres- 

 ent it may be retained as likely to cause less confusion. 



These gobies of curious aspect and habit frequent coastal waters and 

 fresh waters near the sea, and may be recognized by their elongate 

 shape, finely scaled body and head, teeth in jaws in a single row, those 

 in upper jaw conical, those in lower jaw flattened, notched and hori- 

 zontal, a pair of curved canine teeth behind symphysis of lower jaw, 

 eyes erectile, a distinct lower eyelid, dorsal fins well separated, with 

 the spinous rays produced and much longer than the branched rays, 

 and caudal fin lanceolate. 



Two species are recognized from Thailand as follows : 



la. Series of scales between posterior end of second dorsal fin and anal fin 8 to 

 11 ; body with 7 dark oblique cross bands and small oblique cross bands and 

 small opaque blue spots ; caudal fin blackish ; pectoral fins either orange 

 with a black edge or black with an orange edge boddarti 



16. Series of scales between posterior end of second dorsal fin and anal fin 17 ; 

 body dark gray to brown, with irregularly disposed verdigris spots ; dorsal 

 fins with blue spots ; caudal fin with blue spots between rays ; pectoral fins 

 plain pectinirostris 



BOLEOPHTHALMUS BODDARTI (Pallas) 



Gobiiis toddarti Paulas, 1770, vol. 8, p. 11, pi. 2, figs. 4, 5 (Indian Ocean). 



Boleophthalmus toddaerti Johnstone, 1903, p. 300 (Patani States, Peninsular 

 Siam ; Jantbu, Malay States). — Pe:arse, 1933, p. 174 (Paknam). — Fowleb, 

 1934a, p. 159 (Bangkok) ; 1935a, p. 162 (Bangkok, Paknam). 



From Thailand this fish ranges through Malaya and the East Indies 

 to India. In Thailand it is found in salt, brackish, and fresh waters, 

 but does not ascend streams beyond tidal influence. It is particularly 

 abundant in large rivers near their mouths, and is often caught in large 

 quantities in pongpang bag nets, which operate on the outgoing tide or 

 current and catch fish swinuning down stream. Numerous specimens 

 from the Menam Chao Phya and Menam Bangpakong in Central 

 Thailand and the Menam Chao in Southeastern Thailand have been 

 examined. 



Examples up to 15 cm. long are met with in Thailand, and a some- 

 what larger size is probably attained. 



The fish is caught in seines, bag nets, and traps. It is eaten locally 

 and it is also sent to the larger market towns for sale. Sometimes 

 many thousands may reach the Bangkok market from the lower river 

 in a single day. 



In his studies of gobies at Paknam, Pearse (1933) found that the 

 long-intestined Boleophthalmus (ratio of length of body to length of 

 intestine 1 to 1.45) is almost exclusively vegetarian, the percentage by 

 bulk of its intestinal contents being 83.8 filamentous algae and 12.5 



590087 — 45 37 



