145 



Length of head 4 to 4|, of caudal 5, height of body from 2 to 3 

 in the total length. Eyes diameter 3 in length of head, 1| diam. 

 from end of snout, and 1 apart. Profile over snout concave. 

 Teeth six lobate incisors on each side of the upper jaw. Fins 

 dorsal very elevated, fourth dorsal ray highest ; anal also elevated, 

 but not so much so as the dorsal, it begins under ninth dorsal 

 ray. Scales rudimentary, ctenoid. Colour greyish, with nine 

 vertical bands, having white edges, from back to abdomen. The 

 ocular band passes through the eye to the base of the ventral fin ; 

 the second band through the base of the pectoral to the anus. 

 Head sometimes with white spots. Dorsal with four curved blue 

 or white bands, six on the anal and four on the caudal ; these bands 

 are more or less continuations of those on the body, but more 

 vertically curved. Caudal usually spotted with white or a light 

 colour. 



Hob. From the Eed Sea and east coast of Africa, through the 

 seas of India to New Guinea. 



2. Genus NASEUS, Comrnerson. 



Syn. Monoceros, Bl. Schn. ; Naso, Lace"p. ; Aspisurus (Lace"p.), Riipp. ; 

 Axinurus and Priodon, Cuv. & Val. ; : Kens, part., Cuv. & Val. j Calli- 

 canthus, Swainson. 



Branchiostegals four or five ; pseudobranchiae well developed. 

 Body rather elevated and compressed. Eyes high up ; in front 

 of them there is a bony prominence, frontal horn, or crest-like 

 protuberance. Teeth in the jaws in a single ro\v, and sometimes 

 serrated on the edges ; palate edentulous. A single dorsal fin, 

 with few spines (4-6) and many rays. Anal with two spines, its 

 rays similar to those of the dorsal. Ventral 1/3. Scales rudimen- 

 tary, in the form of roughnesses of the skin like shagreen. Free 

 portion of the tail with from 1 to 3 keeled bony plates on either 

 side in the adult; they are indistinct or even absent in young 

 specimens. Air-bladder large, posteriorly forked. Pyloric appen- 

 dages few (5-8). 



These fishes are said to have a very convoluted intestinal tract 

 and to be herbivorous. They are found off Ceylon, and probably 

 may be taken at the Andamans. 



Geographical Distribution. Tropical Pacific and Indian Oceans. 



Synopsis of Indian Species. 



Teeth smooth. Anterior surface of forehead 



prominent 1. 3". tuberosus, p. 146. 



Teeth iinelv serrated. A horn from opposite 



lower portion of eye 2. N. brerirostris, p. 146. 



Teeth smooth. Forehead with a long horn 



from opposite upper third of eye 3. 2V. unicornis, p. 147. 



YOL. II. 1 



