10, COTTOIDS OF NORTH AMERICA. 65 
head slender and elongated, the former tapering quite rapidly away towards the 
tail; both covered with a smooth skin; no teeth on the palatine bones; cleft of the 
mouth not extending beyond the eye; preopercular exhibiting four equal, needle- 
like, and very delicate spines. The first dorsal fin is separated from the second by 
a considerable space, and is much the lower. The great development of the second 
dorsal and the very large eyes might become a specific feature if other species were 
tobe discovered hereafter, for which reason we would not mention them as of 
generic value. The lateral line, the perfectly smooth skin, and the absence of an 
isthmus may become as many generic characters. 
The structure of the skull of Triglopsis exhibits the remarkable character of 
having hollow channels, hitherto only known to exist in Scienoids, and considered 
as a characteristic of this group. We now find amongst Cottoids a similar struc- 
ture, but much less developed in Cotti and Acanthocotti, in which we had over- 
looked it, before we knew the genus Triglopsis. 
This anatomical peculiarity indicates quite a near relationship between Cottoids 
and Sciznoids. The representatives of the latter family in this country are all 
marine, but one. 
TRIGLOPSIS THOMPSONIE, Ginanp. 
Puate II. Figs. 9 and 10. 
Syn. Triglopsis Thompsonii, GIRARD, Proe. Bost. Soc. Nat. Hist. IV., 1851, p. 19. 
Tt will be easy to form a correct idea of the general form of this species by the 
accompanying figures, which, although a restoration from several incomplete indi- 
viduals, we are confident represent its specific features. 
The head is elongated, tapering towards the snout, as the body tapers towards 
the tail. It forms more than the third, and not quite the fourth of the entire 
length. Its upper surface is smooth, gradually sloping towards the snout. Its 
greatest depth is contained twice in its length; whilst its greatest width forms only 
the two-thirds of the latter dimension. The snout is elongated, and thus the 
mouth, which does not extend beyond the entire pupil, is more deeply cleft than in 
Cotti. The lower jaw is slightly longer than the upper. The teeth are very 
minute, proportionally more so than in Cotti. They do not exist on, the palatines, 
but the vomer, besides the crescentic band in front, is provided with a narrow strip 
of similar teeth along the middle line of the posterior branch of that bone. The 
eyes are very large and elliptical; their longitudinal diameter is contained four 
times in the length of the head, the same proportion as in many Cotti, but here the 
head is much more elongated, and accounts for the proportionally greater size of these 
organs in Triglopsis. The anterior nostrils are nearer the orbit than the snout; 
the posterior one is higher up on the frontal line, and still nearer the eye. Both 
pairs of these openings appear to be tubuliform, but the decomposed state of the 
specimens did not permit entire satisfaction on that point. The sides of the head 
are as smooth as the upper surface. The preopercular is the only bone of this 
9 
