52 
U. S. P. R. R. EXP. AND SURVEYS—ZOOLOGY-GENERAL REPORT. 
the “ prickly bullhead,” some of which collected near Astoria, others above the Cascades, at 
Fort Dalles. Their average size is between six and seven inches, a few inches smaller than 
those described by Sir John Richardson. 
The body, viewed in profilers sub-fusiform, tapering gradually backwards ; it is compressed and 
deeper than broad throughout the whole length, though the difference in height and depth 
become greater posteriorly. The dorsal line is slightly arched, whilst the abdominal is 
nearly straight. The head, which is broader than deep, forms the third of the entire length, 
the caudal fin excluded. The upper surface is depressed, the cranial region widely concave, 
without the least trace of ridges, tubercles, or spines, except the minute spines of the turbinal 
bones which are hidden under the skin. The snout is suh-convex above, and rounded upon its 
periphery. The jaws are of equal length, though the inferior lip may project somewhat beyond 
the upper when the mouth is closed. The latter is broad ; the posterior extremity of the 
maxillary extends to a vertical line intersecting the posterior edge of the pupil. The eyes are 
of medium size, sub-circular or elliptical in shape, contained, by their longest diameter, five 
times in the length of the-side of the head ; the interocular space is about one of their diameter ; 
the rostral distance is greater of one-fifth or sixth. The anterior nostril is situated nearly mid¬ 
ways between the rim of the orbit and the margin of the upper jaw. The convexity of the 
preopercle is armed with an acute spine, curved upwards and covered by the skin so as scarcely 
to he seen exteriorly. The inferior edge of the same bony piece exhibits two minor spines 
entirely buried under the integuments. The inferior angle of the opercle has a similar spine 
directed forwards. Finally, the scapular terminates into an acute point concealed under the 
skin and perceptible only to the touch. 
The origin of the first dorsal is situated on a vertical line intersecting the base of the upper 
ray of the pectorals ; it is composed of nine, sometimes ten, rays implanted upon a base not 
quite half the length of the second dorsal, to which it is connected by a low membrane ; the 
sixth and seventh spines are the longest; the outline of the fin forms a convex, somewhat 
depressed line. The second dorsal commences a little in advance of the anus, extending also 
somewhat further hack than the anal; it is composed of twenty-one or two undivided rays, projecting 
beyond their membrane. The caudal is slightly rounded posteriorly ; it is contained six times 
and a half in the total length, composed of nine branched rays and a few simple ones. The 
origin of the anal is situated opposite the fourth ray of the second dorsal; it is not quite so 
deep as the latter is high ; seventeen undivided rays may be observed in it. The interradial 
membrane is more deeply emarginated than in the second dorsal. The ventrals are situated 
posterior to the three inferior rays of the pectorals, and anterior to the upper ones. The 
extremities do not reach the anus. The pectorals are broad, obliquely obovate, composed of 
sixteen or seventeen undivided rays, with the interradial membrane emarginated between all 
of them, though less deeply between the upper rays, which are also more slender than the 
lower ones. Their extremity reaches a vertical line intersecting the anterior margin of the anal. 
Br. VI—VI; D IX, 21; A 17 ; C 3, 1, 5, 4, 1, 2 ; V I, 4 ; P 17. 
Br. VI—VI; D X, 22 ; A 17 ; C 3, 1, 5, 4, 1, 2 ; V I, 4 ; P 16. 
Showing a very slight difference between the rays in specimens of different localities. 
The lateral line is conspicuous, in the shape of a furrow exhibiting a series of contractions. 
From the upper angle of the thoracic arch it takes its course along the flanks, keeping nearer 
the dorsal than abdominal outlines, sometimes deflected under the posterior portion of the second 
dorsal, as in Coitus proper. 
There are no scales ; the skin of the head is perfectly smooth ; the vertex, however, is provided 
