152 
U. S. P. R. R. EXP. AND SURVEYS-ZOOLOGY-GENERAL REPORT. 
2. PLEURONICHTHYS GUTTULATUS, Grd. 
Spec. Char. —Body sub-cylindrical. Posterior extremity of the maxillary extending to a vertical line drawn between the 
pupil and the anterior rim of the orbit. Origin of the dorsal situated opposite the pupil. Ground color of a greyish lead hue, 
besprinkled with whitish spots and black dots. 
Syn. — Pleuronichthys guttulatus, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 137; and, Journ. Bost. Soc. Nat. 
Hist. VI, 1857. PI. xxv, figs. 1—4. 
The body is sub-cylindrical, deeper than in P. coenosus when the depth is compared to the 
entire length. The head is small, and constitutes about the fourth of the total length ; the 
eyes, situated on the right side, are well developed, elliptical, their longitudinal diameter being 
contained three times in the length of the side of the head. The interocular space is exceedingly 
narrow and raised, ridge-like, above the surface of the head. The snout is very blunt and short, the 
mouth small, with its gape oblique upwards, and both jaws even. The posterior extremity of 
the maxillary corresponds to a vertical line drawn midway between the anterior rim of the orbit 
and the pupil. The opercular apparatus and cheeks are scaly ; the branchial fissures moderate, 
and not continuous under the throat. 
The origin of the dorsal fin corresponds to a vertical line drawn immediately in advance of 
the pupil; it is gradually increasing in height to the line of greatest depth of the body, to 
diminish again gradually posteriorly, terminating at a small distance from the base of the caudal. 
The anterior margin of the anal corresponds to a vertical line drawn immediately behind the 
base of the pectoral fins. It is shaped like the dorsal, and terminates evenly with the latter. 
The caudal, which enters about five times in the total length, is rounded upon its posterior 
margin. The origin of the ventrals is situated in advance of the base of the pectorals, in advance 
even of the posterior edge of the opercular apparatus ; they are small and sub-lanceolated; their 
posterior extremity overlaps the vent and reaches the anal fin. The pectorals themselves are 
rather small, and directed obliquely upwards and backwards. 
D 67; A 47 ; 0 4, 1, 8, 7, 1, 3 ; Y 6 ; P 13. 
The scales are quite small, longer than deep, cycloid in structure, with diverging grooves 
upon their posterior section only. The lateral line is slightly arched above the pectoral fins, 
hence nearly straight along the middle of the flanks to the base of the caudal fin. A similar 
mucous line may be traced from the upper rim of the uppermost eye, along the back, giving off 
a connecting branch to the lateral line across the occipital region, and losing itself into the fin 
beyond the middle of the length. 
The ground color is greyish or lead, densely sprinkled all over with black dots and whitish 
spots. The fins being olivaceous similarly dotted with black, but exhibiting fewer white spots. 
List of specimens. 
Catal 
No. 
No. of 
spec. 
Locality. 
When collected. 
Whence obtained. 
Nature of 
specimens. 
Collected by— 
.363 
4 
Tomales bay, Cal. 
1855 
E. Samuels_ 
Alcoholic_ 
E. Samuels_ 
