46 
U. S. P. R. R. EXP. AND SURVEYS—ZOOLOGY-GENERAL REPORT. 
The hranchiostegals are seven in number. The base of the dorsals is sealeless ; that of the 
caudal and pectorals exhibit, as usual, small scales. The upper lateral line does not extend 
beyond the middle of the spinous portion of the dorsal; the fourth is lost about the anal region; 
the divergence of the fifth takes place somewhat nearer the origin of the ventrals than the vent. 
The scales, at large, are of moderate development. 
The upper region of the head and body is almost black; the lower portions of the flanks are 
clouded with black, upon an olivaceous ground. The inferior region of the head and body is 
olivaceous, punctated with black. The fins are olivaceous, maculated with black, the maculae 
upon the anal fin being fewer and much larger than upon the dorsals. 
List of specimens. 
Catalogue number. 
No. of specimens. 
Sex and age. 
Locality. 
When collected. 
Whence obtained. 
Nature of speci¬ 
mens. 
Collected by— 
272 
1 
Adult 
Fort Steilacoom, Puget’s Sound 
1856 
Governor Stevens.... 
Alcoholic. 
Dr. Suckley_ 
273 
1 
_ _(lo_ 
_do_do_ 
1856 
_do_ 
_do_-_ 
_do_ 
OPLOPOMA, Girard. 
Gen. Ciiar. —Body elongated. Membranous flaps above the orbits ; preopercle spinous; snout conical; mouth large ; 
lower jaw longest. Canine teeth upon the premaxillaries, dentaries, front of vomer, and the palatines. Gill openings 
continuous ; hranchiostegals, six on either side. Dorsal fins continuous. Caudal posteriorly sub-crescentic or else concave. 
Insertion of ventrals a little posterior to the pectorals. Body covered with small, cycloid scales. 
Syn .—Oplopoma, Grd. Proc. Acad. Nat. Sc. Philda. VIII, 1856, 135. 
With the general aspect of Chirns and Chiropsis, in the shape of the body, cut of the fins, 
and the presence of a supraocular flap ; this genus is related to Ophiodon by the shape of the 
head, the presence of one lateral line only, and the structure of the scales, which are of the 
cycloid type. Indeed, there is a closer affinity between Oplopoma and Ophiodon than between 
the other members of the same group. The pectoral fins resemble those of Chiropsis more than 
those of Ophiodon. 
OPLOPOMA PANTIIERINA, Grd. 
Plate XYIII, Figs. 1—3. 
Spec. Char. —Body elongated and tapering. Upper surface and sides of bead granular. Preopercular spines few, small 
and blunt. Posterior extremity of maxillary extending beyond the orbit. Origin of anterior dorsal fin situated in advance 
of the convexity of the preopercle. Scales extending over the base of both the caudal and pectoral fins. Blackish brown 
above, reddish brown beneath. Dorsal and lateral regions spotted with black. 
g YN .— Oplopomapaulherina, Grd. Proc. Acad. Nat. Sc. Philad. VIII, 1856, 135. 
The body is very elongated, deepest anteriorly, and tapering gradually from the thoracic 
region backwards. It is compressed, much deeper than broad throughout its entire length ; 
its profile is sub-fusiform. The head, which constitutes a little more than the fourth of the total 
length, is elongated and conical, slightly depressed upon the occipital region and between the 
orbits, sloping rapidly towards the snout. A foliated membranous appendage is to be observed 
