218 L. Agassiz on the Ichthyological Fauna of Western America. 
stitutes a North American representative of that curious type 
first described by Gronovius, under the name of Erythrinus, from 
the Brazils. The genus Erythrinus, divided by J. Muller into 
two genera: Erythrinus proper and Macrodon, was referred by 
him to his family of Characini and afterwards raised by Valen- 
ciennes to the rank of a distinct family under the name of Ery- 
throids, to which he has added the genera Lebiasina Val., from 
Lima, Pyrrbulina Val., from Surinam, and Umbra Kram, from 
Hungary. My genus Melanura is the North American represeut- 
ative of the European Umbra. It may be characterized as fol- 
lows: Body elongated, compressed ; dorsal far behind, extend- 
ing over the space between the ventrals and the anal, as far back 
as the anal itself; ventrals when bent back reaching the anal. 
Mouth opening forwards; lower jaw ‘longer than the upper, 
armed as the intermaxillaries and palatines with small recurved 
velvet teeth; no teeth in the upper maxillaries which form the 
sides of the upper jaw ; pharyngeal teeth like those of the jaws, 
but smaller. Cheeks, opercle and top of the head covered with 
scales. A few large pores along the preopercle, the mastoids 
and on the top of the head. Gill openings very large; mem- 
brane connecting the four branchiostegal rays overlapping one 
another below. No Pseudobranchie. Caudal fin rounded. Hy- 
drargyra limi, A7rt., is another species of this genus, and Professor 
Baird has discovered others in our western waters, which he has 
forwarded to me for comparison and description.* ‘The first spe- 
cies mentioned above, must retain the specific name given to it 
y Rafinesque» I shall therefore call it Melanura annulata. 
The little figure given of this species by Mr. Thompson, in his 
History of Vermont, p. 137, is very characteristic. ] 
Camposroma, Agass. 
As stated above, the Exoglossam dubium of Dr. Kirtland, 
thongh closely allied to the typical species first @escribed 
by Lesueur is not generically identical with it. 
It is true, its pharyngeal teeth have the same general arrange- 
ment, there being an outer row of four teeth on each side, and 
an additional small tooth within that row ; but the teeth them- 
selves inserted in a cluster abreast of the rather spur-like lateral — 
dilatation of the pharyngeal, are more elongated, hardly hooke 
at all, and their inner margin presents a long narrow grinding sut- 
ace, very similar to that of the genus Chondrostoma proper. 
T 
e American fish differs however, in having two rows a 
teeth, while Chondrostoma has six teeth in a single row. 
sides, the form of the mouth is very different in the two, being 
square in Chondrostoma and arched in Exoglossum dubium. 
___* have received another from Davenport, Iowa, through the kindness of Professor 
‘Sheldon. I shall describe all these fishes comparatiy pen another occasion, and 
