Rivers at the foot of the Boutan Mountains, 281 



cles ; the eyes are large and placed midway between the muzzle and 

 operculum. The back ascends from the nape to the dorsal, leaving 

 a narrow ridge in front of that fin ; the third dorsal spine is large, 

 and equal in length to the depth of the body, and serrated behind. 

 The fin rays are 



P. 16: D. £: V. 10: A. % ; C. i3 



There are 42 scales along the lateral line, and 11J in an oblique 

 row from the base of the ventrals to the dorsal, colour blue above, 

 lower parts white ; the fins are pale bluish white. Length 7 inches. 



Habit. — Rivers at the foot of the Sikkim Mountains on the nor- 

 thern frontier of Bengal. 



Tribe, Squammipennes, Cuv. — Fam. Chcetodon, Cuv. 

 CTENOPS, N. Gen. Nob. 



Gen. Char. — Head acute, dorsal small, placed far back 

 on the latter third of the back, anal long, the lower margin 

 of the preoperculum denticulated, anterior suborbitar bone 

 forming the side of the rostrum, is large and denticulated 

 below. 



Obs. — The intestines are about the length of the body, 

 and present two large caecal appendages. 



The teeth are placed in partial tufts, or two incomplete 

 rows on the margins of the intermaxillaries, which are very 

 protractile. No teeth on the vomer or palatines. 



There is but one species known. 



CTENOPS NOBILIS, (J. M.) PI. xxi. /. 1. 



Descr. — The back is obliquely raised almost in a straight line, 

 from the head to the dorsal, which is placed near the tail. Head de- 

 pressed, rostrum elongated, the operculum smooth-edged behind, 

 with a soft projecting scaly point directed backward, the ventrals 

 are preceded by a sharp spine. The fin rays are 

 P. 12: D. 6 -:V.i:A.|:C16. 



Colour mottled grey, with some bright silvery spots. 



