FRESH-WATER FISHES OF SlAM, OR THAILAND 287 



46. Head wholly scaleless ; barbels 2 rostral, 4 maxillary. 



5a. Lateral line complete; a concealed bifid spine far In advance of 

 eye ; eye in posterior third or posterior half of head ; origin of 

 dorsal fin in advance of origin of ventrals ; caudal fin forked or 



deeply emarginate Acanthopsis 



51). Lateral line incomplete; a concealed bifid spine partly under and 

 partly before eye ; eye mostly in anterior half of head ; origin of 

 dorsal fin over origin of ventrals ; caudal fin truncate. 



Neacanthopsis 

 3&. Origin of dorsal fin vi^ell behind base of ventrals; head scaleless. 

 6a. Three pairs of barbels, 1 rostral, 1 maxillary, and 1 mandibular. 



7a. Body very elongate but not anguilliform ; dorsal fin entirely in 



advance of anal Acanthophthalmus 



7&. Body anguilliform ; dorsal fin partly over anal Cobitophis 



e&. Four pairs of barbels, 1 rostral, 2 maxillary, 1 mandibular. 



Acanthopsoides 

 1&. No spine under or before eye Noemacheilus 



Genus BOTIA Gray 



Botia Gray, Zoological Miscellany, 1831, p. 8. (Type, Botia almorhae Gray.) 



Among the loaches of this genus in Thailand are the largest and 

 some of the commonest members of the family. The species are more 

 numerous than in any other local genus except Noemacheilus. 



The large bifid suborbital spines, which can be erected and set in 

 a position perpendicular to the cheek, must be of material value in 

 discouraging attacks by snakes and fishes. Both snakes and fishes 

 have been seen in which the spines of partly swallowed Botia had 

 perforated the sides of the neck or throat, with disastrous results. 



The local species, six in number, may be distinguished easily by 

 their coloration, which in all is striking and in some is brilliant, and 

 by the following characters : 



lo. Body marked by dark cross bands. 

 2a. Cross bands 10 to 15, equal to or wider than interspaces ; no dark median 

 dorsal stripe. 

 3a. Distal margin of dorsal fin either wholly or partly black ; branched dorsal 



rays 9 or 10 lucas-bahi 



3&. Distal margin of dorsal fin pale; branched dorsal rays 11 to 



13 , hynaenophysa 



26. Cross bands 5, much narrower than interspaces; a black median dorsal 

 stripe from tip of snout to base of caudal fin; branched dorsal rays 8; 

 origin of dorsal fin in advance of ventrals and nearer to base of caudal fin 



than to tip of snout ; caudal peduncle deeper than long horae 



16. Body without dark cross bands, at least in adults ; branched dorsal rays 8 or 

 9 ; caudal peduncle deeper than long. 

 4a. Coloration plain. 



5a. A large roundish dark gray spot on caudal peduncle; origin of dorsal fin 

 over base of ventrals and midway between tip of snout and base of 

 caudal fin ; head 3.5 in standax'd length . lecontei 



