270 PROCEEDIXGS OF UNITED STATES NATIONAL MUSEUM. 



Ostrac'ion + Cibotion + Lwtophrijs, Kaup, Arch, llir Naturgeschichte, 1855, pp. 215-219. 

 Ostracion ( — Aracana), Gunther, Cat. Fish Brit. Mus. viii, 1870. 

 Ostracion, FoEY, Eep. Fis. Nat. Cuba, ii, 1868, pp. 439-442. 

 Ostracion, Hollard, Aimales cles Sciences Naturelles, vi, 1856, p. 140. 

 Ostracion -\- Lactophrys + Acanthostracion + Bhinesomus -|- «fcc., Poey, Entim. Pis. Cn- 

 bens. 1876, pp. 174-176. 



DIAGNOSIS OF GENUS. 



Ostraciouts with triagonal, tetragonal, or pentagonal carapaces, the 

 ventral surface always flat or concave, acarinate. Carapace continuous 

 behind anal fin. Ventral spines always associated with frontal spines, 

 if the latter are present. Dorsal fin with 9, occasionally 10 rays. Cau- 

 dal fin with 10 (1 I 8 I 1) rays.* 



As limited by Linnaeus in the tenth edition of the Systema Natures 

 the diagnosis stood as follows : 



164. OsTRACiox Caput: Denies utriuque 10 porrecti, teretes, obtusiusculi Apertura 

 Corpus osse integro obtectmn. Pinnce ventrales nuUsB. 



Habitat . — Tropical and temperate seas, the triagonal species confined 

 to the western Atlantic. 



SYNOPSIS OF AMERICAN SPECIES. 



Carapace triagonal. 

 Carapace spineless O. triqueter, L, 



Carapace with ventral spines — 



* continuo\is behind dorsal O. bicaudalis, L. 



* * open behind dorsal O. TRIGONU8, L. 



Carapace with ventral and frontal spines — 



* dorsal spine not present in adult age, seldom in young O. quadricornis, L. 



* * dorsal spine persistent O. quadricornis subsp. notacanthus. 



(* * * dorsal spine large, associated with four or more ventral spines. 



O. TURRiTUS, Forsk.,L.) 



* The following is as nearly as possible a fac-simile of the original generic description 

 of Artedi : 

 XXXIX. OSTRACION. ' 



Memhrana BrancMostega nulla. 



Figura Corporis insolens, nempe vel glo- 



bosa sen sphcerica, vel subrotunda, vel 



ovata seu oblongo rottmda, vel oblongo 



quadra ngulata., vel conica fere. Cu- 

 tis dura stepe spinis seu aculois magnia 



vel in toto corpore, vel in aliqua ejus 



parte, armata ; interdnm vero glabra. 

 Piinnw Ventrales desunt Numerus Pin- 



narum quinaiius, nempe duae Pecto- 



rales seu laterales ; una dorsi ; una Ani 



una Cauda;. 

 Os exignum : Dentes magni. Ocnli cute 



commune tecti. 



Foramina nar'mm utrinque duo ante ocn- 



los Labia reductabilia dentes ad partem 



tegunt. 



