FAMILY SCIENID^E CORVINA. 77 



THE SHARP-FINNED CORVINA. 



CORVINA OXYPTERA. 



PLATE XXX. FIG. 96. — (CABINET OF THE LYCEUM.) 



Characteristics. Opercle obsoletely serrate, with two spines ; preopercle denticulated. Pecto- 

 ral fins long and pointed. Length eight inches. 



Description. Body oblong, elliptical, compressed. Height to the total length as 1 to 3*5. 

 Back arched, rounded, not gibbous. Scales large, orbicular, wider than long, finely ciliated 

 on the free margins, with 7-10 radiating plaits in front, and festooned on the radical edge. 

 The scales cover every part of the head and jaws, where they are smaller, and ascend high 

 up on all the fins. Lateral line tubular, arising from the upper angle of the branchial aper- 

 ture, and forming a very convex sweep towards the back, with which it is concurrent. Head 

 convex, and forming with the outline beneath a regular oval. Snout obtusely pointed. Eyes 

 large, prominent, - 5 in diameter, and slightly more than their diameters apart. Nostrils 

 anterior to the eyes, approximated ; the posterior transversely oblong, largest ; the anterior 

 with a valvular margin. Opercle with a long triangular flat spine, not extending beyond the 

 pointed_ membrane ; beneath this, at a distance of 0"2, is another short triangular and smaller 

 lancet-shaped spine. The edge of the opercle feels rough to the touch, but is without any 

 visible serratures. Preopercle angular, with from eighty to ninety short acute spines, one 

 rather longer at the angle ; these become effaced on the anterior portion of the lower margin. 

 Mouth moderate, protractile. In the upper jaw, the central part is a free interval. On each 

 side of this free space is a small rounded patch, composed of minute supine teeth directed 

 backward. Anterior to this patch is a tooth on each side, much larger than the others ; the 

 teeth on the sides of the jaw form a small and subequal series. Very minute teeth, reduced 

 to mere asperities, on the vomer and palatines. Similar asperities on the tongue, but the 

 tip is smooth. In the lower jaw are bands of minute recurved teeth, mixed with others of a 

 larger size ; these bands dilate as they approach each other in the middle of the jaw : in 

 front, on each side, is a stout conical tooth directed forward. Branchial membrane with 

 seven rays. 



The dorsal fin compound, and composed of ten spines and nineteen articulated rays ; the 

 spinous portion highest ; the first spine shortest, 0"4 in height ; the second longer, and the 

 third longer and 0'7 in height ; the succeeding spines preserve this height. The spines are 

 very robust, acute, and enveloped in a strong membrane, which is covered with scales nearly 

 to the summit. The rays of the soft portion are slender, and gradually increase in size pos- 

 teriorly, the tips of the last rays reaching nearly to the accessories of the caudal fin. Pecto- 

 ral fin very long, lanceolate ; its tip reaching a point opposite the fifth ray of the soft dorsal, 

 or the third ray of the anal. It is composed of twenty rays, the eleventh and twelfth longest. 

 Counting from above, the rays rapidly diminish beneath these rays. The length of the longest 

 ray is 2'3 ; width of the base, - 5 ; the scales on the base elongated. Ventral fins slightly 

 posterior to the base of the pectorals, and composed of one robust spine and five branched 



