FRESH-WATER FISHES OF BIAM, OR THAILAJ^D 73 



la. A single external gill opening on each side ; pharyngeal teeth jiresent. 



2a. Head and body mostly compressed, not flattened below ; ventral and pectoral 



fins not inserted horizontally ; only outermost ray of pectoral fins simple. 



3a. No suborbital or preorbital spine ; mouth terminal or inferior ; barbels 



none, or 2, or 4 ; pharyngeal teeth in 1, 2, or 3 rows ; air bladder divided 



into 2 anteroposterior parts, not enclosed in bone Cyprinidae 



3&. A suborbital or preorbital spine present or absent ; mouth inferior ; bar- 

 bels 6 or 8; pharyngeal teeth in a single row; air bladder enclosed in 



bone, its posterior part small or vestigial Cobitidae 



2&. Head and body depressed, flattened below ; ventral and pectoral fins in- 

 serted horizontally ; several outer or inner pectoral rays simple ; no sub- 

 orbital or preorbital spine ; mouth inferior ; pharyngeal teeth in a single 

 row ; at least three pairs of barbels ; air bladder reduced, consisting of 



two connected lateral parts enclosed in bone Homalopteridae 



lb. Two external gill openings on each side; mouth inferior; pharyngeal teeth 

 absent ; upper and lower lips coiled together in postlabial groove ; barbels 

 absent ; ventral and pectoral fins horizontal Gyrinocheilidae 



Family CYPRINIDAE: Minnows and carps 



It is in this family that the fresh-water fishes of Thailand reach 

 their greatest development as regards number of genera and species 

 and number of individuals. The number of species exceeds those 

 known from French Indo-China, from Malaya, from the Indo- 

 Australian Archipelago, or from Burma. Even in India, with seven 

 times the area of Thailand, this family is scarcely more numerously 

 represented. 



For convenience the following subfamilies may be recognized : 



Iri. Upper lip separated from skin of rostrum by a deep groove; base of upper 



lip more or less covered by a pendulous rostral fold; mouth anterior, 



subinferior, or conspicuously inferior. 



2a. Abdomen compressed into a sharp edge; no barbels; pharyngeal teeth in 



2 or 3 rows ; dorsal fin with 7 to 10 branched rays ; arising in posterior 



half of body and inserted opposite anal or opposite space between anal 



and veutrals ; anal fin with 12 to 48 branched rays Abraminae 



2&. Abdomen rounded or flat, not compressed into a sharp edge ; barbels present 

 or absent ; pharyngeal teeth in 1, 2, or 3 rows. 

 3a. Generally a knob at symphysis of lower jaw fitting into an emargination 

 in upper jaw; barbels rostral and maxillary, but one or both pairs 

 may be absent ; dorsal fin with 6 to 16 branched rays and without any 

 osseous simple rays, arising behind origin of veutrals ; anal fin with 5 

 to 17 branched rays; lateral line if present with an abrupt down- 

 ward curvature anteriorly, if complete running in lower half of 



caudal peduncle Basborinae 



3b. No knob at symphysis of lower jaw ; barbels rostral and maxillary, but 

 one or both pairs may be absent ; dorsal fin with 7 to 30 branched rays 

 and with or without an osseous simple ray, which may be smooth or 

 denticulated, arising before, over, or behind origin of ventrals; anal 

 fin with 5 to 9 branched rays and with or without an osseous simple 

 ray; lateral line (with two exceptions) running along middle of 

 caudal peduncle__^^ — ^-^ — -. — ,-^^_^-^,^ — Cyprininae 



