CATALOGUE OF VERTEBRATES. 745 

 POMACANTHUS, Lac. 



(Chsetodon." Holacanthus.) 

 P. ciliaris, L. Angel-fish. Isabelita. 



Preoperculum with a strong spine at its angle ; brownish 

 olive ; each scale with a crescent of lighter shade ; nape with a 

 dark-brown spot, enclosing blue center; cobalt-blue markings 

 on various fins, spines, &c. ; yellow also on fins ; scales ciliate ; 

 soft dorsal and anal with anterior rays prolonged as long stream- 

 ers. Dorsal rays, XIV, 20; anal rays, III, 20; scales, 8 — 

 50^30. 



" This beautiful species is seldom met with along our coast. 

 A specimen is in the Philadelphia Academy's museum, that was 

 taken in Delaware Bay. It is a southern species." 



Family ACANTHURIDiE. 



(Teuthidse.) 

 Surgeons. 



Teeth in one row, incisor-like; tail with one or more movable 

 spines or bony plates on each side ; mouth small, low ; eye high up ; 

 premaxillaries movable, but not protractile; gill rakers obsolete; a 

 gill slit behind fourth arch; gill openings restricted to the sides; 

 pelvic bone long ; ventrals thoracic. Herbivorous fishes. 



ACANTHURUS, Bl. & Schn. 

 (Acronurus, Gunth.) 



nigricans, L. [Chxtodon, phlebotomus.) Surgeon-fish. 



A movable, lancet-like spine on each side of tail ; body ovate- 

 oblong, covered with minute ctenoid scales; operculum short; 

 branchiostegals five ; vertebrae, 9 + 13 ; color brownish ; opercle 

 with a black margin ; sides with very narrow transverse bands ; 

 body not much elevated ; profile somewhat convex and snout 

 longish ; fins high ; caudal emarginate. Dorsal rays, IX, 25 ; 

 anal rays. III, 23. 



" This species is very rare upon our coast, and can only be 



