346 ACRONUEID^. 



with vertical striiB. A broad silvery band across the opercles and 

 the thorax. Branchiostegals five. 



Small herbivorous fishes from the tropical seas. 



1. Acronurus orbicularis. 



Acanthurus orbicularis, {Quoy 8f Gaim.) Cui\ 8f Val. x. p. 237. 



B.5. D.|. A.|. 



The height of the body is four-fifths of the length (the caudal fin not 

 included). Yellowish, with some blackish blotches ; fins yellowish. 

 Island of Guam. 



2. Acronurus melanurus. 



Acanthiu'us melanurus. Cur. 8f Val. x. p. 240; Bleek. Amb. ^ Cer. p. 271. 

 D ^ A 1 



rhe height of the body is three-fifths of the length (the caudal fin 

 not included). The second dorsal spine is longer and stronger than 

 the follnwing.v The cleft of the mouth is situated at some distance 

 below the level of the. orbit. Body brownish ; vertical fins blackish. 



East Indian Seas. 



a. Borneo. Presented by Vice- Admiral Sir E. Belcher, C.B. 



3. Acronurus brevispinis. 



D. -f-. A. |. V. 1/2. 



The height of the body is contained once and four-fifths in the 

 length (the caudal fin not included). The first dorsal spine is very 

 short ; the second stouter, but shorter than the following. The cleft of 

 the mouth is situated somewhat above the middle of the arch formed 

 by the upper and lower profiles of the snout, immediately below the 

 level of the orbit. Reddish- white, with the usual silver)^ cross-band. 



Hah. ? 



a. Fifteen lines long. — None of the soft dorsal and anal rays can be 

 disting-uished, and are probably lost. There appear to be only 

 two soft anal rays. The crests on the upper side of the head 

 are serrated. 



4. Acronurus argenteus. 



Acanthurus argenteus, Qkoi/ &; Gnhit. Joy. Urnn. Zool. p. 372. pi. 63. 

 fig. 2 ; Cuv. c^ Val. x. p. 239. 



D. ^. A. -. 



The height of the body is one-half of the length (the caudal fin 

 not included). Nearly uniform dull yellowish. 

 Sandwich Islands. Marianes. Ascension Island. 



a. Adult. Ascension. Voyage of H. M.S. C'hanticlecr. 



