Il. COTTOIDS OF NORTH AMERICA. 43 
little less than the depth. The head is much flattened above, gradually slop- 
ing towards the end of the snout. Its width is equal to the space comprised 
between the end of the snout and the base of the preopercular spine. The mouth 
is very broad; its angles, however, do not extend beyond the pupil. The palatine 
asperities are more conspicuous than in any of the other species which exhibit 
traces of them. They occupy an oblong and elongated area on the surface of their 
bones. The eyes are proportionally small; their diameter is contained nearly six 
times in the length of the head. The interorbito-frontal space measures a quarter 
of an inch, and accordingly, is broader than in any other species. The anterior 
and posterior nostrils are both tubular. The posterior one, the largest, is situated 
above in advance of the orbit; the anterior one is nearer the orbit than the end of 
the snout. The preopercular spine, directed obliquely upwards, is short, stout at 
its base and very acute at the tip. Underneath, and directed downwards, there 
exists a second very minute, blunt spine. The isthmus is five-sixteenths of an inch 
wide. 
The surface of the head exhibits numerous holes all along the tracks of the 
cephalic channels of the lateral line, by means of which a direct communication is 
established with the surrounding medium. Several of these holes exist on the 
snout in the vicinity of the nostrils. They appear more distinct on the specimen 
figured, on account of the decomposed state of the epidermis which is deprived of 
all its pigmentum. 
The origin of the first dorsal is one inch and a quarter from the extremity of 
the snout. Its rays, seven in number, occupy a longitudinal space of five-eighths 
of an inch, the last ray sending its membrane to the very base of the first ray of 
the second dorsal. The latter is composed of sixteen rays, the central ones exhibit- 
ing a slight bifurcation on their summit, without, however, solution of continuity. 
It extends on a basis of one inch and a quarter, that is, exactly twice the length of 
the first dorsal. Its anterior edge is nearly of the same height with the middle, 
and its decrease takes place gradually towards the posterior edge, distant from the 
caudal three-sixteenths of an inch. The origin of the anal fin is opposite the 
third ray of the second dorsal. It contains thirteen unbranched rays. The ex- 
terior margin of this fin is convex, the middle rays being a little longer than those 
of the second dorsal. The central rays of the caudal are twice subdivided; the 
posterior margin of this fin is subtruncated; differing in this respect from that of 
C. Bairdii. The insertion of the ventral fins takes place, as usual, under the 
pectorals; but in this species it is considerably more in advance of the first dorsal 
fin, whilst in C. Bairdii, it is situated immediately under the first ray of the 
anterior dorsal. They are composed of four soft, jointed, but unbranched rays, the 
second and third being the longest. The spiny ray is very slender. When bent 
backwards, the tip of these fins is far from reaching the vent, thus proportionally 
shorter than those of CO. Bairdii. Their more advanced position is not sufficient 
to account for the difference. The pectorals are broad, with a crescentic base of 
insertion; they are composed of fourteen rays, the four uppermost but two, are 
bifureated, a character quite peculiar to this species amongst the American ones. 
