214 
U. S. P. R. R. EXP. AND SURVEYS-ZOOLOGY-GENERAL REPORT. 
limb is also more slender. The bead is more elongated, more conical than in M. lateralis , and 
larger than in M. frater cuius. The mouth is larger than in either of the two species just alluded 
to. The fins are well developed ; the dorsal and anal both are deeper than long; their formula 
reads: 
D 2, 8 + 1 ; A 2, 8 + 1 ; C 8, 1, 9, 8, 1, 7; V 1, 9 ; P 17. 
The scales are sub-elliptical, somewhat smaller on the abdominal region than on the dorsal 
region. 
References to the figures .—Plate XLVI, fig. 1, represents Mylocheilus caurinus, size of life. 
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. 
Correspond’ g 
No. of teeth. 
No. of 
spec. 
Age. 
Locality. 
When 
collected. 
Whence obtained. 
Nature of 
specimens. 
Collected by— 
213 
2770 
12 
Adult 
Astoria, 0. T_ 
1855 
Lt. W. P. Trowbridge 
Alcoholic. 
Lieut. Trowbridge ... 
2. MYLOCHEILUS LATERALIS, Agass. & Pick. 
Plate XLV, Figs. 5 — 8. 
Spec. Char. —Head constituting the fifth of the total length. Snout sub-conical. Posterior extremity of the maxillary 
extending to a vertical line drawn across the hind nostril. Diameter of the eye entering five times and a half in the length of 
the side of the head. Anterior margin of dorsal fin equi-distant between the extremity of the snout and the insertion of the 
caudal. Base of anal fin contained fourteen times in the total length. 
Syn. — Mylocheilus lateralis, Agass. & Pick, in Amer. Journ. of Sc. 2d ser. XIX, 1855, 231 .—Grd. in Proc. Acad. Nat. Sc. 
Philad. VIII, 1856, 169. 
Although the dorsal and anal are both deeper than long, the length of the latter is propor¬ 
tionally less than in the preceding and the following species. The fins present the general 
aspect, with a few differences in the number of the rays: 
D 1, 8 + 1; A 1, 9 ; C 8, 1, 9, 8, 1, 9 ; V 1, 10; P 19. 
The scales exhibit, also, the same general characters ; their anterior margin, however, ap¬ 
pears to be more irregular ; hence their outline assumes a somewhat less elliptical form. 
References to the figures. —Plate XLV, fig. 5, represents Mylocheilus lateralis , size of life. Fig. 
6, a scale from the dorsal region. Fig. 7, a scale from the lateral line. Fig. 8, a scale from 
the abdominal region. 
List of specimens. 
Catal. 
No. 
Correspond’g 
No. of teeth. 
No. of 
spec. 
Age. 
Locality. 
When 
collected. 
Whence obtained. 
Nature of 
specimens. 
Collected by— 
212 
27G9 
3 
Adult 
Fort Steilacoom, 
Puget’s Sound, 
Wash. Ter_ 
1853 
Gov. 1.1. Stevens_ 
Alcoholic. 
Dr. Geo. Suckley_ 
