100. TRACHYPTEEID^. 617 



33. AC A TV T HI! 51 US Blocli & Schneider. 



(Acronurus Gthr. ; young.) 

 (Forskfil; Blacli & Schneider, Ichthyol. 1801, 211: type Chwtodon chirurgus Bloch.) 



Body ovate-oblong, compressed, covered with minute ctenoid scales. 

 Mouth rather small, with broad lobate or serrate incisors, which are 

 sometimes movable. A movable spine in a groove on each side of tail. 

 One dorsal fin, low and long, with 7-9 (sometimes fewer) spines; usually 

 a procumbent spine before the dorsal ; anal with 2 or 3 spines. Ven- 

 tral rays I, 5. Caudal eniargiuate. Gill openings moderate, oblique, 

 separated by a broad isthmus; operculum very short; preopercle ob- 

 lique, with entire edge. Branchiostegals 5. Intestinal canal elongate. 

 Yertebrtvi 9 + 13. (axavOa, spine; oupa, tail.) 



Ao -]hBB'iu > g'M Bl. & Sc.hn. Surgeon -ftsh ; Doctor-fish. 

 Brownish; opercle with a black margin; sometimes a whitish band 

 across tail at base ot caudal; sides with dark transverse bauds; vertical 

 fins with oblique, parallel, dark streaks. Body oblong, compressed, 

 and not greatly elevated ; profile little convex, somewhat undulated. 

 Vertical fins high ; caudal moderately emargiuate. Head 3 in length; 

 depth 2. D. IX, 25; A. Ill, 23. West Indies; occasional northward. 



(Bloch & Schneider, 214; Gunther, iii, 329, in part; Poey, Anales Soc. Hist. Nat. 

 Espagn. 1880, 245.) 



9. Ao cEB*MSeffi:s Bloch & Schneider. Blue Surgeon; Bar'bero. 



Deep bluish brown, with undulating pale blue longitudinal lines, 

 especially on the dorsal and anal fins, where they become straight and 

 oblique. Upper profile of snout slightly concave. Caudal fin more or 

 less deeply forked, the lobes bordered with pale in the adult; caudal 

 spine glassy, amber-colored; opercles striate. Body very deep. Depth 







] in length. D. IX, 2S; A. Ill, 25. West Indies; occasional northward. 



(Bloch & Schneider, 1801,214; Poey, Anal. Soc. Hist. Nat. Espagn. 1880,244: Acan- 

 tJiurus nigricans Goode, Bull. U. S. Nat. Mas. v, 42 (not of L.): Acanthiirua cceruleus 

 Gtmther, iii, :];!G.) 



FAMILY C. TRACHYPTERID^. 

 ( The King-of-the-Herrings.) 



Body elongate, strongly compressed, naked, the skin smooth or 

 prickly. Lateral line present. Head short, the mouth rather small, 

 terminal, with feeble teeth; premaxillaries protractile; opercles un- 

 armed. Eye large, lateral. Branchiostegals G. Gill-membranes sepa- 



