238 U. S. P. R R. EXP AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
v 
of the tail to the caudal fin. The specimen figured nd described is twelve inches and a half 
in total length. 
References to the figures .—Plate LIII, fig. 1, represents Orthodon mierolepidotus, somewhat 
reduced in size. Fig. 2, a scale from the dorsal region. Fig. 3, a scale from the lateral line. 
Fig. 4, a scale from the abdominal region. 
List of specimens. 
Catal. 
No. 
Cor. No. 
of teeth. 
No. of 
spec. 
Age. 
Loca ity. 
When col¬ 
lected. 
Whence obtained. 
Nature of 
specimen. 
Collected by— 
206 
2764’ 
i 
Adult. 
San Francisco, Cal.. 
1855 
Lt. R. S. Williamson.. 
Alcoholic . 
Dr. John S. Newberry. 
ALGANSEA, Girard. 
Gen. Char. —The head is sub-conical, more or less pointed, though rounded upon its periphery. The mouth being of medium 
size, slightly oblique upwards, its angles never extending beyond the anterior rim of the orbit; the jaws themselves terminate 
evenly. The eye is of moderate development. There is a narrow isthmus between the gill openings. The body short and 
stoutish, quite compressed, covered with scales of medium or of large size, the lateral line being sub-medial, slightly deflexed upon 
the middle of the abdomen. The fins are rather moderate in development; the origin of the ventrals is situated opposite to 
the anterior margin of the dorsal, the posterior margin of the latter never reaching the anterior margin of the anal. The caudal 
fin is emarginated posteriorly. The pharyngeal bones are moderately strong; the upper and lower branches nearly of equal 
strength, though the lower is somewhat longer than the upper. The convexity is strongly marked and dilated. The teeth are 
of the cultriform kind of the grinding type, disposed upon a single row of four or five, as follows: 4—4 or 5—5. The uppermost 
stand boldly out above the surface of the bone. 
Syn.— Algansea, Grd. in Proc. Acad. Nat Sc. Pliilad. VIII, 1856, 182. 
The typical species of this genus (A. tincella ) is Mexican ; it is figured and described in the 
Report of the United States and Mexican Boundary Commission. It differs widely from the 
three following species found within the limits of the United States. 
1. ALGANSEA BICOLOR, Grd. 
Spec. Char —Head contained four times and a half in the total length. Eye of moderate size; its diameter entering four 
times and a half in the length of the side of the head. Posterior extremity of the maxillary extending to a vertical line drawn 
across the nostrils. Anterior edge of dorsal fin nearer the insertion of the caudal than the extremity of the snout. Insertion 
of ventral fins is somewhat in advance of the anterior margin of the dorsal, and nearer the base of the caudal than the extremity 
of the snout. Scales large. Back and sides of a metallic bluish black tint, intermingled, upon the lower half of the flanks, 
with a golden hue. The inferior region is pure white or yellow. Fins bluish grey at their base, olivaceous at their periphery. 
Syn. — Algansea bicolor, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 183. 
The body is thickest anteriorly, and tapers backwards ; the nape is slightly swollen. The 
head enters about four times and a half in the total length. The ventrals are inserted a little 
in advance of the anterior margin of the- dorsal. Of all the species hitherto known of this 
genus, the one here referred to has the largest scales, five rows of which may be counted from 
the origin of the ventrals to the lateral line, and nine from the lateral line to the anterior 
margin of the dorsal: in all fifteen rows. They are deeply imbricated, nearly as deep as long, 
anteriorly sub-truncated, with a few radiating grooves upon their posterior section only. The 
rays of the fins are as follows : 
D 1, 9 ; A 1, 9 ; C 6, 1, 9, 8, 1,7; V 9 ; P 16. 
