L. Agassiz on the Ichthyological Fauna of Western America. 227 
the centre, in such a manner as to give rise to radiating furrows 
diverging on all sides In Phoxinus the ridges are fewer, and 
they are only distinctly interrupted upon the posterior and lat- 
eral fields of the scale, and scarcely at all upon the anterior seg- 
ment, so that the anterior margin exhibits few furrows, if any. 
The tubes of the scales in the lateral line are also different. In 
Chrosomus they are narrower, more tubular and closed, and 
not extending far beyond the centre of growth of the scales; in 
Phoxinus they have the appearance of broad chamels occupying 
almost the entire field of the scale from margin to margin. ‘The 
number of teeth assigned to Phoxinus by Heckel is not quite so 
constant as he seems to believe; I find occasionally only four 
teeth in the outer row instead of five, and only one in the inner 
row instead of two; but I have never seen two rows in Chro- 
somus. ‘T'he form and comparative size of the fins are about the 
same in the two genera; they differ only in relative position, the 
dorsal being placed farther back in Phoxinus than in Chrosomus. 
The mouth is terminal and yet when it is closed, the snout pro- 
jects slightly beyond its crescent shaped outline ; this feature is 
particularly marked in Chrosomus. * However, when outh 
18 opened the lower jaw of Chrosomus projects more than that of 
Phoxinus. Neither of these fishes have barbels. In Chrosomus 
as Well as in Phoxinus, the males differ from the females in hav- 
ing brighter colors, especially in the spawning season. 
he Rutilus ? ruber of Rafinesque, which he has himself 
hever seen, and of which he says that it may belong to his genus 
Ratilus, or to any of this tribe, a slender fish, only two inches 
ong, Compressed and of a fine purple red, can be nothing but 
Chrosomus erythrogaster. ‘There is no other fish in the Ohio ba- 
SiN aiswering to this description. 
Piychocheilus, Agass. 
There are few Cyprinide in which the mouth is widely cleft ; 
few which have a slender appearance and whose form indicates 
Swift motion, Among the best known of that character I may 
any of the many genera which have been estab- 
Cyprinide. Its mouth is far more widely open 
