32 
U. S. P. R. R. EXP. AND SURVEYS-ZOOLOGY-GENERAL REPORT. 
lary extends to a vertical line drawn posteriorly to the orbit. There is a great disproportion in 
the size of the scales which cover the cheeks and the opercular apparatus, being a good deal the 
smallest on the cheeks. Finally, the position of the ventral fins, and that of the anus, differ 
from their situation in the other species. 
The head enters four times and a half in the total length ; it is sub-conical, with the snout 
rounded and the jaws equal, or nearly so. In large specimens the lips become very fleshy, and, 
if any difference he observed in the respective length of the jaws, the upper one will be found 
slightly protruding beyond the lower. The tongue is smooth. The eye is sub-elliptical, and of 
moderate development, its horizontal diameter entering about seven times in the length of the 
side of the head. Both nostrils are nearer the orbit than the extremity of the snout. The 
convex and external edge of the preopercle is serrated or denticulated. A single flattened 
spine may he observed upon the opercle. 
The origin of the first dorsal is situated a little in advance of the insertion of the ventrals 
and backwards of the base of the pectoral fins. It is as high as the second dorsal, but longer 
upon its base, than the latter. The caudal fin enters about six times in the total length. The 
anal is as deep as the second dorsal is high, though a good deal shorter. 
Br. VII: YJI; D XIII, 20 ; A 15 ; C 5, 1, 8, 7, 1, 4 ; V I, 5 . P 13. 
“ XII “ 13 “ “ 14. 
The scales are of moderate development, deeper than long, except in the lateral line. They 
are minutely pectinated upon their posterior section. Sub-truncated anteriorly, they are rounded 
upon the remaining three edges. Diverging furrows are observed upon the anterior section 
only. The base of the soft portion of both the second dorsal and anal fins, as also the caudal 
to a great extent, are covered with scales. The cranial region is likewise scaly. 
The ground color of the dorsal region is reddish olive, olivaceous upon the sides, and yellowish 
or whitish beneath. The hack and upper part of the flanks are spotted or blotched with black 
or brown. The belly and inferior surface of the tail are unicolor. The side of the head is 
mottled or barred in the young, in which we also observe upon the dorsal region, in addition to 
the marking already alluded to, three transversely oblique and large blotches. The pectorals 
are spotted with black upon their base, otherwise they are unicolor, yellowish, like the ventrals 
and anal. The dorsals and caudal are transversely spotted with black. 
References to the figures .—Plate XI, fig. 5, represents Stizostedion boreus , somewhat reduced 
in size. Fig. 6 is 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. 
Catalogue number. 
No. of specimens. 
Sex and age. 
Locality. 
When collected. 
Whence obtained. 
Nature of specimens. 
Collected by— 
385 
1 
Adult 
Fort Sarpy, Nebraska_ 
1854 
Colonel Vaughan_ 
Alcoholic ........ 
Dr. Hayden.. 
386 
1 
-.do.. 
MiDdriver, Missouri___ 
1853 
Governor Stevens_ 
.do.._ 
Dr. Suckley.. 
510 
1 
..do.. 
Fort Union, Missouri_ 
1856 
Lieut. G. K. Warren_ 
Dr. Hayden.. 
