316 Records of the Indian Museum. [Vol. XXIV, 



(iii) The air-bladder consists of two lateral chambers en- 

 closed in a bony capsule. This type of bladder is characteristic 

 of, the genus N emachilus and is not to be met with in any species 

 of Botia. 



(iv) There are six barbels, four rostral and two maxillary, 

 but the rostral barbels are not united at their base as is the case 

 in Botia. 



(v) The shape of the mouth, the structure of the lips, jaws 

 and of the scales is quite different from any species of the genus 

 Botia that I have examined. 



The following is an artificial key to all the known species of 

 the genus Botia ' : — 



Group I. Barbels six (Hymenophysa). 



I. Eye in middle of head [Commencement of dorsal equidistant from 



tip of snout and base of caudal] ... ... ... B. mitltifasciata. 



II. Eye not in middle of head. 



A. Eye nearer end of operculum than that of snout or 

 almost wholly in posterior hall of head. 



i. Length of head equals depth of body [Suborbital 



spine extending to below posterior margin of eye ; 



a broad black bar at base of caudal] ... ... B. modesta.* 



2. Length of head greater than depth of body. 



a. Suborbital spine extending beyond eye in both 



directions ... ... ... ... B. superciliai'is. 



b. Suborbital spine extending to below middle 



of eye ... ... ... B. hymenophysa.* 



B. Eye nearer end of snout than that of operculum. 



1. Suborbital spine not extending to below hind 



margin of eye ... ... ... ... B. curta.* 



2. Suborbital spine distinctly extending to below hind 

 margin of eye. 



. a. Interorbital space twice as wide as orbit ; "ground- 

 colour yellowish, the body ornamented with five 

 black bands " ... ... ... ... B.variegata. 



b. Interorbital space three to four times as wide as 

 orbit; " ground-colour brownish olive, without 

 distinct markings on the body " ... ... B. pratti. 



Group II. Barbels eight {Botia s.s.). 



I. Eye in middle of head ... ... ... B. helodes. 



II. Eye not in middle of head. 



A. Length of snout considerably more than that of re- 

 maining part of head. 



1. Body marked with two broad bands ... ... B. macr acanthus.* 



2. Body marked " with irregular and partly confluent 

 brown cross bands, which enclose larger and smaller 



round whitish spots " ... .. ... B, rostrata. 



B. Length of snout either equal to or less than that of 

 remaining part of head. 



I. Eye almost in posterior half of head. 



a. Head and body marked with a number of narrow 



oblique vertical bands ... ... ... B. striata.* 



b. Head and body marked with a few broad vertical 

 bands or reticulations. 



' The species marked with an asterisk are present in the collection of the 

 Zoological Survey of India. 



