CYPRINIDA. — XXVI. 55 
(Hybopsis tuditanus Cope; Alburnops taurocephalus Hay.) (Lat. 
watchful.) 
56, NOTROPIS Rafinesque. (AMERICAN MINNows.) 
(Minniuus Rafinesque, etc., etc.) 
(As now understood, this genus contains upwards of a hundred 
species of small Cyprinoids, all of them confined to the waters of 
E. N. A. They are feeble fishes, of rather low organization, none 
of them of any value as food to man, but of great importance as 
food for the larger predatory fishes. ‘The species are highly vari- 
able, readily affected by surrounding conditions, while the per- 
manently distinctive characters are few. The identification of 
species in this group is therefore very difficult, and in the case 
of young specimens often impossible. ‘The following analysis must 
be used with caution, as all characters are subject to occasional 
or individual variations.) (véros, back; rpdms, keel; but the 
back is not keeled. Rafinesque’s types had been shrivelled by 
drying.) 
a. Teeth 4, 4, or 1, 4-4, 0, or 1, 4-4, 1 (sometimes 1, 4-4, 2 in N. hudsonius). 
&. Scales not closely imbricated, not notably deeper than long; D. inserted 
nearly over V.; A. short, its rays 7 or 8. 
c. Teeth 4-4, the grinding surface more or less developed. 
d. Lateral line usually incomplete; scales before D. large, 13 in num- 
ber. (Hemitremia Cope.) 
e. Snout very obtuse; lower jaw not projecting. 
97. N. bifrenatus (Cope). Body slender, the tail contracted ; 
upper lip on level of lower part of pupil; jaws subequal, eye large, 
3 in head; lateral line very short. Straw-color, with jet-black 
lateral band, bordered with orange on snout. Head 44; depth 41. 
D.8. A.7. Scales 5-36-3. L. 2. Mass. to Md. (Lat., two- 
bridled.) 
98. N. anogenus Forbes. Very similar to N. heterodon, but 
with lateral line usually complete; the mouth very small and very 
oblique, the lower jaw included, the upper lip above level of pupil; 
snout short, blunt. Dusky, a very distinct lateral band and a black 
spot at base of C.; a black speck on each pore of lateral line. 
Head 41; depth 42. A. 7. Lat. 1. 34 to37. L.1}. W.N.Y. 
(Ithaca, Meek) to Ill. (a, without; yévus, chin.) 
ee. Snout pointed; lower jaw projecting. 
99. N. heterodon Cope. Body rather stout; eye 3 in head; 
lateral line usually developed about half-way, sometimes nearly per- 
fect. Olive, sides with dusky plumbeous band, fainter than in 
preceding. Head 4; depth 4. A. 8. Scales 5-36-3. L. 23. 
Teeth crenate. W.N. Y. to Kans.; common. (Other specimens 
from Ind. and IIl. have lateral line complete, and teeth 2, 4-4, 2. 
