848 Bulletin 47, United States National Museum. 



Rhinoberyx, GILL, Proc. Ac. Nat. Sci. Phila., 1862, 237, (brachyrh?jnchm); young; scales said to be 

 25; may represent a distinct genus. 



Body oblong, moderately compressed, the ventral outline nearly 

 straight, the back a little elevated, the tail very slender. Head com- 

 pressed, narrowed forward. Operculum with a strong spine above, below 

 which the edge is sharply serrated ; a strong spine at the angle of pre- 

 opercle. Orbital ring, preorbital, preopercle, interopercle, subopercle, 

 occiput, and shoulder girdle with their edges sharply serrate. Mouth 

 small, terminal, the lower jaw projecting in the adult; in the young 

 (which constitute the supposed genera Rhynchiclithys and Rhinoberyx) 

 the snout is much produced. Maxillary broad, striate, with a supple- 

 mental bone. Eye excessively large. Scales moderate, closely imbri- 

 cated, the posterior margin strongly spinous. Lateral line continuous. 

 Dorsal deeply emarginate, the spines usually 11, depressible in a groove; 

 soft dorsal short and high ; anal with 4 spines, the first and second quite 

 small, the third very long and strong, the fourth smaller; caudal widely 

 forked; both lobes with the rudimentary rays spine-like; ventrals 

 large, I, 7, the spine very strong. Species numerous, remarkable for the 

 development of sharp spines almost everywhere on the surface of the 

 body. (6/lof, whole; n'evrpov, spine; spinous all over.) 



a. Preopercular* spine long, tapering, acute ; third anal spine very long, more than half 



depth of body. 

 6. Mouth moderate, lower jaw extending to below first %io% length of eye. 



c. Scales small, 50 to 55 in lateral line; upper lobe of caudal longer than lower, fal- 

 cate; soft dorsal and anal elevated, pointed at tip, this character subject to 

 variation. ASCENSIOXIS, 1233. 



cc. Scales moderate, about 45; depth of body 2f in length; membrane of front spines 

 of dorsal black. SICCIFEB, 1234. 



ccc. Scales rather large, 38 to 42 in lateral line; caudal lobes nearly or quite equal. 

 d. Maxillary extending to below middle of eye. 

 e. Depth of body greater than length of head. 



/. Third anal spine 1% in head. SUBOEBITALIS, 1235. 



/. Third anal spine If in head. CORUSCUS, 1236. 



ee. Depth of body equal to length of head. BBACHYPTERUS, 1237. 



eee. Depth of body less than length of head; dorsal without black; cheeks 



. without white dots. MARIANUS, 1238. 



dd. Maxillary extending to below first third of eye; dorsal with black markings. 



VEXILLAUIUS, 1239. 



bb. Mouth small, maxillary reaching to below first fourth of eye; upper lobe of caudal 



longer; cheek with a white blotch. oscums, 1240- 



aa. Preopercular spine short, flattish, notched at tip; third anal spine short, its length about 



% depth of body; soft dorsal and anal low, rounded. SANCTI-PAULI, 1241. 



1233. HOLOCENTRUS ASCENSIONIS (Osbeck). 

 (MATEJUELO; SQUIRREL-FISH; SOLDADO; WELSHMAN.) 



Head 3f ; depth 3f ; eye 2* ; snout 4*. O. XI, 15 ; A. Ill, 10 ; scales 

 5-50 to 54-7; cwca 25; vertebrae, 11+16. Mouth small, little oblique, 

 maxillary scarcely reaching middle of eye. Longest dorsal spines more 



* Little dependence can be placed on this analytical key, as several species are imperfectly 

 known and of doubtful validity. 



