498 Journal of the Asiatic Society of Bengal. [Sept., 1910. 



guishing shape to the species and makes it appear as it were 

 possessed of a double chin. The upper edge of the occipital 

 crest is always in the same straight line with the snout. 



Teeth. — Eight incisors in each jaw, the lower jaw being 

 slightly prominent and prolonged. 



Colour. — Upper part of the body glaucous grey with 

 deeper coloured margin and some deeper blotches interspersed 

 in the upper part of the body, lower part being silvery white ; 

 there is a blurred blackish spot in front and around the base of 

 the first dorsal spine ; the portion of the membrane between 

 the first dorsal and the rest of the rays of the spinous dorsal 

 is immaculate, but the portion of the membrane that is above 

 the level of the second ray of the spinous dorsal and is at- 

 tached to the upper half of the first dorsal spine is intensely 

 black. The upper half of first dorsal spine itself is also 

 blackish. From below the eyes to almost end of the snout 

 (that is, excluding upper lip and premaxillary portion), the 



wi 



snout is concave. 



fourth of the length of eye is coloured blackish, which sud- 

 denly loses itself in the siivery white colour of the buccal area 

 which is similarly coloured as the lower part of the body. 

 Soft dorsal, pectoral, anal, and caudal fins, ventral spines and 

 lips are all dull white. There is no black spot in front of ven- 

 tral spine as in Tr. biaculeatus (Bloch). 



The principal points in which the new species differs from 

 the rest of the known species belonging to the genus may be 

 more conveniently stated in a tabular form as follows : 



In Tr. brevirostris, Tr. indi- \ T , T __ - f u~ 



cus, and Tr. niiuhofi-the ' In the n6W s P ecies - the 

 snout is straight. 



In Tr. strigilifer — the second^ 



ray of spinous dorsal is more In the new species— the 



than half as long as the first. second ray of spinous 



In Tr. blochi and Tr. biacu- j> dorsal is normally half 

 leatus and all the rest — the as long as the first dor- 

 second ray is more than half sal spine, 

 as long as the first. J 



Length of head in total length > 

 excluding caudal — 



In Tr. blochi, 3$ — 3| times. | In the new species 

 In Tr. biaculeatus. 3| times. i length of head three 



In Tr. brevirostris", 3|— 3J f times in total length 



times. 



In Tr. indicus, 3|— 3* times. 

 In Tr. nieuhofi, 3£— 3 "times, j 



excluding caudal. 



