ACANTHOPTERYGII. 165 



AcANTHURus, Laccp. andBl. — Harpurus, Forst. 



Teeth trenchant and notched; a strong movable spine on each side 

 of the tail, that is as sharp as a lancet, and inflicts severe Avounds on 

 those who carelessly handle these fishesj hence their vulgar name of 

 Surgeons. They inhabit the hot parts of both oceans.(l) 



The dorsal of some species is very high.(2) 



Some have a sort of brush composed of stiff hairs, before the 

 lateral spine.(3) 



In others again the teeth are deeply notched, or pectinated on one 

 side.(4) The 



Prionurus, Lacep. 



Only differs from the preceding genus in the armature of the sides 

 of the tail, which consists of a suite of fixed, horizontal and trench- 

 ant blades. (5) 



Naseus, Commers. — Monoceros, B1. Schn. 



Sides of the tail armed with fixed trenchant blades: but the teeth 

 are conical, and the front projects in a kind of horn or knob above 

 the muzzle; but four rays in the branchi^ and three soft ones in the 

 ventrals; the skin resembles leather. (6) 



losus, Quoy and Gaym., Zool. Voy. Freycin., p. 369; — Centrogaster fusccsccns, 

 Houttuyn.; — Chsetodon guttatus, Bl. 196; — Jlmph. marmoratus, Quoy and Gaym., 

 Voy. Freycin. J Zool., pi. 62, f. 1 and 2; — Jlmph. magniahac, lb. f. 3; — Centrogas- 

 ter argentatus, Hoiitt., and several others to be described in our Icthyolog'y. 



(1) Chsetodon cMrurgus, Bl., 208; — Thelitis hepatus, L.; Seb. Ill, xxxiii, f. 3; — 

 Ac. glauco-pareius, Cuv., Seb., Ill, xxv, 3, which appears to be the true Chsetodon 

 nigricans, L. ; — CJiset. triostegus, Brousson., Dec. Icht. No. 4, or Jtcanthure zehre, 

 Lacep., which is also his Chsef. zebre, III, xxv, 3; — .Re. guttatus, Bl., Schn.; — Jlc. 

 suilhts, Cuv., Renard, I, pi. xiv, f. 82; — Chwt. lineatus, L.; Seb. Ill, xxv, 1; — Chset. 

 Achilles, Broussonnet; — Chset. meta, Russ. 82; — Chaet. sohal, Forsk., of which Lacep. 

 has very improperly made a genus under the name of Ajnsurus; — Ac. striatus, 

 Cuv.; Paniiigu, Renard, pi. 1, f. 8; — Ac- argente, Quoy and Gaym. Voy. Freycin., 

 p. 63, f. 3; — Chset. nigrofuscus, Forsk.; — Chset. nigricans, Bl. 203, which is not that 

 of Linnjeus. 



(2) Ac. velifer, Bl. 427. 



(3) Ac. scopas, Cuv., Renard, I, pi. xi, 101. 



(4) Ac. ctnedon, Cuv., anew species. 



(5) Prionure microlepidote, Lacep., An. Mus. IV, p. 205; — ./Icanthurus scalpruvi, 

 Langsdorf. 



(6) Naseus fronticoriiis, Cuv., Lacep. Ill, vii, 2, BL, Schn., pi. 42, Hasscq., it. 

 pal. 332; — Nas. tandock, Ren. I, iv, 23; Valent. 518; — Chxt. unico)-nis, Forsk., differ 

 from our first species. — JSfas. brevirostris, Cuv-, Ren. I, xxiv, 130; — Nas, iumifrons,' 



