FRESH-WATER FISHES OF SIAM, OR THAILAND 529 



3&. Upper part of opercle scaled. 



80. Body and head light brown, a round dark brown spot on each scale of 3 

 abdominal rows of scales ; all fins except pectorals black or blackish, 

 pectorals dusky ; a small black spot at upper base of caudal fin. 



atripinnatus 



86. Body and head olive, with a blue or pearly spot on each scale and some 



blackish spots along side ; all tins except pectorals black ; pectorals 



yellow, with black margin masoni 



Sc. Body and head green, with about 5 black dorsal blotches, the first on 

 head behind eye, the last under posterior end of second dorsal, and 

 with about 5 roundish black spots along middle of side ; at upper end 

 of gill opening a large round lustrous emerald-green spot ; side of 

 head with small green siwts; each scale on side of body with a 



golden green spot caninus 



1ft. Thirty-four to 40 scales in longitudinal series; scales in transverse series 

 12; predorsal scales 30 to 32; general color olivaceous to dusky, with a 

 series of indistinct dark blotches along side ; a large emerald-green shoulder 

 spot, and nape and sides of head variously spotted with green ; many 

 scales along sides have emerald-green spots ; tins variously tinged with 

 pink, blue, or violet ; second dorsal with a submarginal green band and a 

 light edge; caudal, anal, and ventrals dark green to blackish, caudal with 

 a lavender upper edge, anal sometimes gray, with a submarginal green 

 band viridipunctatus 



ACENTROGOBIUS ORNATUS (Ruppell) 

 Oohius ornatus Ruppeill, 1828, p. 135 (Massaua, Red Sea). 



One of the most beautiful of the local gobies, this species ranges 

 from the east coast of Africa to Australia, the East Indies, Philip- 

 pines, Samoa, and Fiji. The numerous specimens taken in Thailand 

 have come from Koh Samui, in the western part of the Gulf of Siam; 

 from Koh Chang, Koh Chik, Sriracha, and the Chantabun Estuary, in 

 the Southeastern district. 



The maximum length of local specimens is 8.7 cm. Examples of 

 7 to 8 cm. are common. 



This is the only local species in which the upper pectoral rays are 

 free and sillry, a feature that, with the characters noted in the key, 

 makes identification easy. 



The fish shares with some of the related forms the vernacular name 

 of pla bu hua to (big-head goby). 



ACENTROGOBIUS SIMULANS (H. M. Smith) 



RhinogoMus similis Smith, 1931a, p. 43 (Bandon Bight). 



Rhinogobius simulans Smith, 1931c, p. 64 (substitution of new specific name). 



Described in 1931 from specimens, 7.7 and 6.6 cm. long, from Bandon 

 Bight, an arm of the Gulf of Siam in Peninsular Thailand, this 

 species has not since been reported. Through an oversight to which 

 Dr. Carl L. Hubbs drew the writer's attention, the specific name 



