G16 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



tui. Dorsal spines 8 to 11. (Pomacanthue). 

 S>6>. P. a :v iiat us (L.) Lac. 



Dark brown, anteriorly plain ; lower jaw pale ; each scale with a daik 

 spot and a whitish edge; young' with yellowish vertical bands, some- 

 nines spotted with black; base of pectorals sometimes yellow. Scales 

 on body small, nrm; large and small ones irregularly mixed. Head with 

 shagreen, formed of rudimentary scales. Dorsal and aiial extremely 

 falcate, the anterior soft rays two-thirds the length of the body in the 

 adult; dorsal spines very low; last anal spine long. Month small; 

 gill-rakers short; gill-membranes very slightly joined to the isthmus 

 mesially. D. IX, 30; A. Ill, 24; Lat, 1. 80-100; cosca 15; vert. 10 + 

 14. West Indies, north to Garden Key, Florida. 



(Chwiodon arcnatiifi L. Syst. Nat.: Pomacanthus paru, cinguJatiift, qninquccinctits, and 

 urcuatus Cuv. & Val. vii, 202-211: Pomacanthus parti (Uintlirr, iii, 55.) 



FAMILY XCIX.-ACANTHURIDJE * 



(The Surgeons.} 



Body oblong, compressed and usually elevated, covered with very 

 small scales ; lateral line continuous. Tail armed with one or more 

 movable spines or bony plates. Eye lateral, high up; pivorbital very 

 narrow and deep. Nostrils double. Mouth small, low; each jaw with 

 a single series of incisor-like teeth; vqmer and palatines toothless; pre- 

 maxillaries somewhat movable, but not protractile; maxillary short; 

 gill-rakers obsolete; pseudobranchia 1 large; gills 4, a slit behind the 

 fourth; gill-membranes attached to the isthmus, the openings thus re- 

 stricted to the sides. A single d ;rsal lin, with strong spines, the spi- 

 MOIIS part of the lin about as long as Ihe soft part; anal lin similar, 

 shorter; ventral iins present, thoracic, mostly I, 5 (never I, 4, I, as in 

 'r<'ittliiilid(r). Pelvic bone long, evident thiough the skin, as in HtiliNtidw, 

 with which group the Ac(i>itltnri(l(c have numerous allinities. I'vloiic 

 cceca rather lew. Air-bladder large. Herbivorous fishes of the tropicai 

 seas; genera 5 or more; species nearly SO, most of them belonging to 

 Acanthurus. 



t 

 I. roiinriiln- (JiiiilluT, iii, :{56.) 



a. Tail with a movable- laurel -liKc ^\>\\n- on cucli sidr: incisors serrate. 



ACAN mi i:rs, :!::o. 



"Callrd Tuilliiiliili;- in tin- key on pa^f 78. 



