188 



and Labrador. I cannot help thinking that there are two species 

 confounded under the name of grcRiilandicus, the comparative 

 study of which will alone enable us to determine. Should they 

 prove to be distinct, the name of variabilis could be restored for 

 the species of the western coast of the Atlantic. 



Next to the Acanthocottus must be placed the genus Tra- 

 CHiDERMis Heckel. characterized by a rough skin, and teeth on 

 the palatine bones ; as for the rest, similar to the foregoing in 

 its general appearance. The body is perhaps more fusiform and 

 the armature of the head and of the opercular apparatus less 

 developed. The head is very depressed, and the mouth deeply 

 cleft. But one species of this genus is known, the T. fasciatus 

 Heck.* from the Philippine Islands. It is a fish of a small size. 



I shall preserve the name of Cottus Artedi, for the fresh water 

 species, having but one small spine at the angle of the preo- 

 perculum, and sometimes another still smaller, always hidden 

 under the skin and perceptible to the touch only, at the lower 

 margin of the suboperculum. The head itself is very depressed, 

 more or less truncated in front, generally broader than high, 

 but always very uniform, being scarcely detached from the 

 body unless by its more considerable breadth. The mouth is 

 less deeply cleft than in the Acanthocotti. Like the latter they 

 have teeth on the intermaxillaries, on the lower maxillaries 

 and on the front of the vomer. Sometimes at a younger age, 

 the palatine bones are rough, indicating rudimentary teeth ; 

 these bones become smooth in the adult. Nostrils double, as in 

 the Acanthocotti. The body is also smooth, scaleless, and taper- 

 ing to the tail. The first dorsal is always less high than the sec- 

 ond ; the back is but little arched and projects little or not at all 

 above the nape. The ventral fins have three soft rays in some 

 species and four in some others. The lateral line is sometimes 

 interrupted, as in the greater number of American species,t 

 sometimes continuous throughout the total length of the body, as 

 is the case with all the species of the old world. 



The generic name of Uranidea has been given to a species of 

 the genus Cottus by a mistake of its author. Nevertheless, if the 



* Annalen des Wiener Museum, Vol. ii. 1837, p. 159, PL 9, figs. 1 and 2. 

 t Mr. Heckel has made of it one of the characters of his C. gracilis^ the single 

 American species which he saw. 



