FISHES — EMBIOTOCOIDAE — HOLCONOTUS RHODOTERUS. 



193 



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 Beading, California, by Dr. J. F. Hammond, United States 

 Army, and by Dr. John S. Newberry, under Lieutenant K. S. Williamson. 



Plate XXVI, fig. 14, represents the embryo of Mysterocarpus trashii, size of life. 



List of specimens. 



Catal. 

 No. 



No.of 

 spec. 



561 

 562 



Sex and 

 age. 



Locality. 



Adult.. Fort Reading, California.. 

 Young .\ do 



When 

 collected. 



1855 

 1855 



Whence obtained. 



Nature of 

 specimens. 



Lieut. R. S.Williamson. Alcoholic. 

 Dr. J. F. Hammond do. . . . 



Collected by — 



Dr. Newberry. 

 Dr. Hammond. 



HOLCONOTUS, 



A gass, 



Gen. Char. — Head well developed. Mouth small ; jaws equal ; lower one projecting slightly when mouth opens. Lips 

 thin; lower one free all around. Prema.xillaries protractile to a considerable e.\tcnt. 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 articilated 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 on 

 apparent row of scales, tapering posteriorly. 



Syn. — Holconoius, Acass. ia Araer. Journ. of So. 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 but 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 deprossion 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 KHaDGTERMS, A gass. 



Plate XXXV ; Plate XXXVI, Figs, x— 4 ; and, Plate XXVI, 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. Eranchiostegals, 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. — Holconoius rhodolerus, Agass. in Amer. Journ. of Sc. second series, XVII, 1854, 368. — ^Grd. in Proc. Acad. Nat. 

 Sc. Philad. Vir, 1854, 141 and 152 ; and, VII, 1655, 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 



