FRESH-WATER FISHES OF SIAM, OR THAILAND 259 



Subfamily Garrinae 



Under this subfamily name (based on the oldest generic name) 

 there may be grouped a few genera with local representatives in which 

 an outstanding character is the coalescence of the upper lip with the 

 skin of the rostrum. The paired fins are for the most part horizontal ; 

 in some of the genera the lower lip is modified into a sucking disk, 

 and the mouth is distinctly inferior. The genera of this subfamily, 

 two of which are peculiar to Thailand, may be differentiated as 

 follows : 



la. Upper and lower lips continuous; lower lip modified into a circular or 



elliptical sucking disk ; snout bearing horny tubercles ; branched dorsal 



rays 7 to 9. 



2a. Edges of sucking disk free and papillate ; upper lip crenulated ; 2 or no 



rostral barbels, 2 maxillary barbels which may be vestigial or absent; 



simple dorsal rays may be partly ossified Garra 



2&. Edges of sucking disk free and entire; upper lip entire; 2 rostral and 2 

 maxillary barbels well developed ; simple dorsal rays nonosseous. 



Discolabeo 



1&. Upper and lower lips not continuous ; lower lip not modified into a sucking 



disk ; upper lip crenulated or fringed ; snout with or without horny 



tubercles ; branched dorsal rays 8 or 10 ; simple dorsal rays nonosseous. 



3c. Branched dorsal rays 8. 



4a. Body subcylindrical; snout with a small, movable lateral lobe; no rostral 



pores or tubercles ; upper and lower lips connected by a frenulum ; 



barbels rostral and maxillary or only rostral Epalzeorhynchos 



4&. Body compressed ; snout with no lateral lobe ; rostral pores and tubercles 

 present; lips not connected, upper lip joined to lower jaw by a 

 frenulum ; barbels rostral and maxillary, but either pair may be 



absent .- Crossocheilus 



3&. Branched dorsal rays 10; body compressed; rostral pores and tubercles 

 present ; lips not connected, upper lip joined to lower jaw by a frenulum ; 

 no barbels Mekongina 



Genus GARRA Hamilton 



Oarra Hamilton, Fishes . . . River Ganges, 1822, p. 393. (Type, Cyprinus 

 lamta Hamilton.) 



The fishes of this genus are found mostly in mountain streams, 

 where they are aided in maintaining their position by means of a 

 small sucking disk on the lower lip that enables them to adhere to 

 stones. The genus, called Discognathus (Heckel, 1843) by Glint her, 

 Day, Weber and de Beaufort, and other authors, occurs in Africa, 

 Syria, Arabia, Burma, Ceylon, and Borneo, as well as in Thailand. 



Four local species may be recognized as follows : 



la. One pair of barbels (rostral) ; a broad black lateral band from head to base 

 of caudal fin. 

 2a. Caudal peduncle rather long, equal to or longer than head and 1.5 to 2 

 times its depth. 



