108 TBLEOSTEI. PIIYSOSTOMI. 



In some specimens the under surface of the pectoral spine aud first 

 ventral ray are striated. Caudal emarginate, lower lobe the" longer. 

 The thoracic sucker has about 14 transverse folds. The free portion 

 of the tail about three times as long as deep at its base. Colour 

 blackish, with some large, irregular, yellowish blotches. Fins 

 yellow, with black bands. 



Hob. Darjeeling and Khasi hills, attaining 7 to 8 inches in 

 length. 



3. Genus EXOSTOMA, Blyth. 



Syn. Chimarrichthys, Sauvage. 



Gill-openings narrow, the membranes confluent with the skin of 

 a broad isthmus. Head depressed and covered superiorly with soft 

 skin. No thoracic adhesive apparatus. Mouth inferior, with the 

 lips reflected around the whole or most of its circumference, and 

 usually covered with tubercles. Nostrils close together, separated 

 by a barbel. Eight barbels. Teeth in the jaws in several rows ; 

 palate edentulous. Anterior dorsal fin with a rudimentary spine 

 and six rays ; adipose fin long and low. Pectorals vertical in their 

 upper, horizontal in their lower half, the spine enclosed in skin. 

 Ventral composed of six rays, inserted some distance behind the 

 rayed dorsal, shaped like the pectoral. Caudal square, emarginate 

 or forked. Air-bladder enclosed in bone. 



This peculiar mountain genus has its lips adapted for a sucker, 

 the chest likewise appears to form a flat adhesive surface, bounded 

 by the striated rays of the pectoral and ventral fins. 



Geographical Distribution. From the upper waters of the Indus, 

 along the Himalayas and the Mishmee Mountains in East Assam, 

 to Eastern Tibet on the confines of China ; also in Tenasserim. 



Synopsis of Indian Species. 



Lower labial fold uninterrupted. Anal com- 

 mences much nearer the base of the caudal 

 than that of the ventral 1. E. labiatum, p. 108. 



Lower labial fold interrupted. Anal com- 

 mences in last third of the distance between 

 ventral and base of caudal 2. E. blythii, p. 100. 



Snout more pointed. Caudal forked 3. E. berdmwei, p. 10Q.' 



Lower labial fold interrupted. Anal com- 

 mences nearer the base of the ventral than 

 that of the caudal 4. E. stoliczlxc, p. 110. 



114. (1.) Exostoma labiatum. 



Glyptosternon labiatus, McClell. C. J. N. If. ii, p. 588. 

 Exostoma labiatum, Day, Fish. India, p. 501 (see synou.). 



