56 ACEONUEID^E. 



Family ACRONURID.E. 



ACANTHURUS, Schn. 



177. Acanthurus triostegus. [338.] 



Seba, iii. 25. 4 ; Russell, i. pi. 86. 



Chaetodon triostegus, L. Syst. Nat. i. p. 463. 



Acanthurus triostegus, Bl. Schn. p. 215 ; Cuv. fy Val. x. p. 197 ; Giinth. Fish. iii. p. 327. 



hirudo, Benn. Fishes of Ceylon, pi. 11. 



Mozambique. From Mauritius to Polynesia and New Zealand. 



178. Acanthurus matoides. [18, 575.] 



Acanthurus matoides, Cuv. fy Val. x. p. 204 ; Giinth. Fish. iii. p. 330. 



annularis, Cuv. fy Val. x. p. 209 (immature specimens with a whitish caudal ring) . 



blochii, Cuv. <5f Val. x. p. 209 (immature specimens without a whitish caudal ring) . 



xanthopterus, Cant. Mai. Fish. p. 202, pi. 4. 



D.^g. A. g^. V. 1/5. 



Var. a [18]. Body neutral-tint coloured, a broad bluish or yellow band across the 

 base of caudal, a blue line along the base of dorsal, and an indistinct yellowish 

 band from below the eye across forehead. Dorsal and anal brown, with three or 

 four longitudinal blue bands, sometimes absent on the spinous portion of the former ; 

 anal sometimes with a blue margin. Exterior half of pectorals yellow or brownish. 



Aden. Zanzibar. Length 9^ inches. 



Var. b [575]. Colour brown, with indistinct yellow undulating lines ; posterior margin 

 of branchiostegous membrane black ; a yellow band from orbit to orbit above nostril ; 

 several irregular yellow and blue lines on the snout ; a yellowish band across base of 

 caudal ; a narrow yellow line along base of dorsal. Dorsal yellowish brown, with a 

 blue basal line ; beyond this there is a series of blue spots, round on the spinous, and 

 elongate on the soft portion ; above these there are several longitudinal bluish lines and 

 a bright-blue margin. Ventrals longitudinally striped, alternately yellowish and bluish ; 

 pectorals bluish black inferiorly and yellowish superiorly. 



Zanzibar. East-Indian seas. Polynesia. Length 9^ inches. 



179. Acanthurus leucosternon. [365.] 



Acanthurus leucosternon, Benn. Proc. Zool. Soc. 1832, p. 183; Bleek. Nat. Tydschr. Ned. Ind. 1856, 



Batoe, iii. p. 237 ; Giinth. Fish. iii. p. 340. 

 — — delisianus, Cuv. if Val. x. p. 193 ; Guer. Iconogr. Poiss. pi. 35. f. 2. 



Zanzibar. Mauritius. Ceylon. Butoe. 



