270 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



Osfrac'ion -(- C'lhotion -\- Lwtopliri/s, KAUr, Arcli. Ivir Naturgeschichte, 1855, pp. 215-219. 

 Ostracioii ( — Aracana), GtJNTHER, Cat. Fish Brit. Mns. viii, 1870. 

 Osiraclon, PoEY, Rep. Fis. Nat. Cuba, ii, 1838, pp. 439-442. 

 Osiradon, Hollard, Annales des Sciences Naturelles, vi, 1856, p. 140. 

 Ostracion -\- Lactophrys -{- Acavihostracion -\- Bhinc8omus -{- &c., Poey, Emim. Pis. Cii- 

 bens. 1876, pp. 174-176. 



DIAGNOSIS OF GENUS. 



O.stracionts with triagonal, tetragonal, or pentagonal carapaces, the 

 ventral surface always flat or concave, acariuate. Carai)ace continuous 

 behind anal fin. Yentral 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 liiaited by Linnteus iii the t^uth edition of the Systema Xaturcc 

 the diagnosis stood as follows : 



164. OsTiJACiON Caput: Denies titriuqnc 10 porrecti, teretes, obtnsiuscnli Apertura 

 Corpus osse iutegro obtectum. rinncc ventrales niillse. 



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

 to the western Atlantic. 



SYNOPSIS OF AMERICAN SPECIES. 



Carapace triagona l. 



Carapace spineless O. triqueter, L. 



Carapace with ventral spines — 



*continnons behind dorsal O. bicaudalis, L. 



**open behind dorsal O.trigonus, L. 



Carapace with ventral and frontal spines — 



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



* * dorsal spine persistent O. quadricorxis snbsp. xotacaxthus. 



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



O. TURRiTUS, Forslv.,L.) 



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

 of Artodi : 

 XXXIX. OSTRACION. 



Membrana Branchiostega nulla. 



FUjura Corporis insolens, nempe vel glo- 



bosa sen sphfcrica, vel subrotunda, vel 



ovata sen oblougo rotunda, vel oblongo 



quadrangulata, vel conica fere. Cu- 

 tis dura stepe spinis sen aculeis magnis 



vel in toto corpore, vel in aliqua ejus 



parte, armata ; interdum vero glabra. 

 rUnrxe Vcntraies desunt Niimerus Pin- 



uarum qninarius, ueuipo duae Pecto- 



rales sen laterales ; una dorsi ; una Aui 



una Caudtt. 

 Osexiguum: Dcntes magni. Oculi cute 



commune tecti. 



Foramina narium utrinque duo ante ocu- 



los Labia reductabilia dentes ad partem 



toKunt. 



