96 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



chydamo and that there is intergradation in the two characters on 

 which the two genera or subgenera have been separated. Thus, Danio 

 naganeTims Chaudhuri, from India, may have 8 branched dorsal rays, 

 in combination with a complete lateral line; Danio {Brachydanio) 

 shanensis Hora, described from the Shan States of Burma, has 7 

 branched dorsal rays and normally an incomplete lateral line, but a 

 specimen with practically complete lateral line is recorded by Hora and 

 Mukerji (1934), and a specimen from Northern Thailand with fully 

 complete lateral line is figured by Fowler (1934a, fig. 65) without 

 comment. The species D. (B.) shanensis is aberrant in this respect 

 and seems to be the only one in the Bimchydanio group in which the 

 lateral line may be either complete or incomplete ; all the other Indian, 

 Burman, and Thailand species, about eight in number, conform with 

 the original subgeneric definition, having 7 branched dorsal rays and 

 the lateral line either incomplete {a^uticephaliis, alboUneatits, 

 sondhii) , or entirely lacking, {choprae Hora, kerri H. M. Smith, nigro- 

 fasciatus (Ddiy) ^ pulcher H. M. Smith) , or either incomplete or absent 

 (rerio [Hamilton]). Another species, hereinafter referred to, from 

 Northern Thailand, combines a complete lateral line with 7 branched 

 dorsal rays, and for convenience may be recognized as the type of a 

 new subgenus named below. 



The Thailand species of Danio fall into three groups, or subgenera, 

 which may be indicated as follows : 



Danio in strict sense : Lateral line complete. Branched rays in dorsal fin 8 

 to 17; branched anal rays 11 to 17; barbels present (maxillary and rostral or only 

 maxillary) or absent; a preorbital spine present or absent. 



Bra<;hydanio: Lateral line absent or incomplete. Branched dorsal rays 6 or 7; 

 branched anal rays 10 to 13; barbels present or absent ; no preorbital spine. 



Allodanio (new subgenus) : Lateral line complete. Branched dorsal rays 7; 

 branched anal rays 10; barbels (rostral and maxillary) present; no preorbital 

 spine. 



The local species, numbering nine, may be identified by the use of 

 the following key : 



la. Lateral line complete. 

 2a. Branched dorsal rays 8 to 17 ; branched anal rays 11 to 17. Subgenus Danio. 

 3a. Rostral and maxillary barbels present; origin of anal fin well behind 

 origin of dorsal fin. 

 4a. A small backward-projecting spine on anterior orbital rim. 

 5o. Body deep, its depth 2.65 to 2.75 in standard length ; least depth of 

 caudal peduncle about 1 in its length; origin of anal fin 1 eye 

 diameter behind vertical from dorsal origin ; 1 scale between lateral 

 line and base of ventral fin ; general color light brown, with 5 pale 



(blue or white) longitudinal bands on body regina 



56. Body more elongate, its depth 3.75 to 4 in standard length; least 

 depth of caudal peduncle about 2 in its length ; origin of anal 

 fin 2 eye diameters behind vertical from dorsal origin; 1.5 or 2 



