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U. S. P. R. R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
jaw by a broad frenum. The nostrils are large and situated close to tlie anterior rim of the 
orbit. The position of the eye is quite elevated, being of medium size, sub-circular, having its 
horizontal diameter comprised a little over four times in the length of the side of the head. 
The scales on the cheeks are very crowded, disposed without much regularity. On the 
opercle five rows may distinctly be counted ; they are smaller on the sub-opercle. The branchi- 
ostegal rays are six on either side and well developed. 
A line drawn vertically from the origin of the dorsal fin passes behind the base of the 
pectorals. The spinous portion is composed of eleven rays, occupying nearly two-fifths of the 
base of the entire fin. Its upper outline is sloping from the first to the fifth spine, whence it is 
nearly straight to the eleventh ; from the anterior articulated ray backwards it is regularly 
descending. The articulated rays bifurcate twice. The caudal fin is contained a little more 
than five times and a half in the total length. Its middle rays exhibit a bifurcation of the fifth 
degree. The base of the anal enters about four times and a half in the total length. There are 
three spines at its anterior margin, the second and third nearly as long as the articulated rays. 
Then, in the male, the fin is separated into two portions by a flattened and sub-triangular ray, 
anteriorly of which the other rays are swollen and their membrane thickened as in Einbiotoca 
and other genera of the same family. The articulated rays, however, are mostly all divided. 
The rays adjoining the flat triangular one are more or less irregular and exhibit numerous sub¬ 
divisions. The base of the anal extends a little more backwards than that of the dorsal. The 
insertion of the ventrals is situated under the vertical line of the third dorsal spine. These fins 
are broadly developed, extending beyond the vent but not to the anterior margin of the anal, 
and their rays exhibit a partial bifurcation of the fifth degree. The pectorals are well developed, 
their extremity reaching the vertical line of the second articulated ray of the dorsal. The rays 
bifurcate three times with traces of a fourth. The formula of the fins is : 
Br. VI: VI; D XI, 24-; A III, 7 + 1 + 16 = 24 ; C 4, 1, 6, 6, 1, 5 ; V I, 5 ; P 1, 26. 
The scales (figs. 3—5) are of moderate development, deeper than long, rounded upon their 
superior, posterior, and inferior edges, and sub-truncated anteriorly. Their shape is subjected 
to great variations in the lateral line and on the abdominal region. This is particularly the 
case along an area opposite the base of the anal, where they are at the same time much smaller 
than on any other region. On the other hand, on a vertical area immediately above the 
triangular spine of that fin they assume a disproportionate size. Along the base of the rays 
constituting the posterior portion of the same fin, scales may be observed of an elongated shape, 
forming a double row anteriorly. The lateral line is formed of about sixty-eight scales ; seven 
or eight longitudinal rows may be counted between the latter and the dorsal groove, and about 
twenty-four rows on the line of greatest depth below the lateral line. The dorsal groove 
extends from the eighth dorsal spine to about the ninth articulated ray ; the sheath above is 
composed of three irregular series of scales, variable in size, tapering to one row and assuming 
a more oblong shape. 
The ground color above the lateral line is bluish grey or olive, somewhat mottled. The sides 
are silvery with a golden reflect, particularly on the sides of the head. Irregular and, mayhap, 
indistinct transverse bands descend along the flanks from the dorsal region. The dorsal, caudal, 
anal, and ventral fins are olivaceous or yellowish grey. The pectorals are yellowish or straw- 
color. 
