193 
PISHES—EMBIOTOCOIDAE—HOLCONOTUS RHODOTERUS. 
sexes do not differ in their coloration, nor indeed is there any trace of those thickened rays upon 
the anterior third of the anal, and which are so characteristic of the sexes throughout this 
family of fishes. 
They were collected at Fort Reading, California, by Dr. J. F. Hammond, United States 
Army, and by Dr. John S. Newberry, under Lieutenant R. S. Williamson. 
Plate XXVI, fig. 14, represents the embryo of Hysterocarpus traskii, size of life. 
List of specimens. 
Catal. 
No. of 
Sex and 
Locality. 
When 
Whence obtained. 
Nature of 
Collected by— 
No. 
spec. 
age. 
collected. 
specimens. 
561 
i 
Adult.. 
Fort Reading, California.. 
1855 
Lieut. R. S. Williamson. 
Alcoholic... 
Dr. Newberry. 
562 
2 
Young 
.do. 
1855 
Dr. J. F. Hammond • • •. 
Dr. Hammond...... 
HOLCONOTUS, Agass. 
Gen. Char. —Head well developed. Mouth small; jaws equal; lower one projecting slightly when mouth opens. Lips 
thin; lower one free all around Premaxillaries protractile to a considerable extent. Teeth small, slender, sub-conical, 
slightly curved, disposed upon a double row on the upper jaw and one only on the lower. Spinous portion of dorsal fin higher 
than the soft. Anterior articulated rays of anal mostly all divided, and preceded by three spines shorter than the other rays. 
Scales rather large. Lateral line concurrent with the dorsal outline. No scales on the fins. Dorsal groove extending from 
opposite middle of spinous portion of dorsal fin to beyond the middle of soft portion of same fin. Sheath formed of but one 
apparent row of scales, tapering posteriorly. 
Syn. — Holconotus, Agass. in Amer. Journ. of Sc. second series, XVII, 1854, 367.—Grd. in Proc. Acad. Nat. Sc. Philad. 
VII, 1855, 322. 
This genus approximates Ennichthys by the shape of the dorsal fin and the nature of the 
lower lip. It is^ however, distinguished from the latter in the presence of hut one row of teeth 
on the lower jaw, larger scales on the body, and their entire absence from the fins. 
As regards the dorsal fin, there is a slight depression in its outline, which depression 
corresponds to the point of union between both the spinous and articulated portions ; the last 
spine being a little shorter than the first articulated ray. On a superficial examination, 
however, the outline of that fin seems to descend regularly from the fourth or fifth anterior 
spinous ray to its posterior extremity. The first and second anterior spines are always shorter 
than the articulated rays. 
HOLCONOTUS RHODOTERUS, Agass. 
Plate XXXV; Plate XXXYI, Figs. 1—4 ; and, Plate XXYI, Figs. 7 and 8. 
Spec. Char. —General form elongated, neither elliptical nor fusiform. Frontal region sub-concave. Head sub-conical ; 
mouth small; posterior extremity of maxillary not quite reaching the vertical of anterior rim of orbit. Eyes rather large and 
circular. Branchiostegals, five. About forty-four scales in lateral line. Bluish grey or olive above, silvery or yellow upon the 
sides, with rose colored spots disposed in longitudinal series. 
Syn. — Holconotus rhodoterus, Agass. in Amer. Journ. of Sc. second series, XVII, 1854, 368.— Grd. in Proc. Acad. Nat. 
Sc. Philad. VII, 1854, 141 and 152 ; and, VII, 1855, 322. 
The average size of this species is from five to six inches in total length. The body is very 
much compressed, elongated, in the shape of either an ellipsis or a contracted spindle, the 
25 a 
