838 FISHES—CYPRINIDZA. 
Habitat, Ohio Valley to Red River of the North, in clear brooks. 
Diagnosis.—This the only little Minnow in Ohio having long intestines 
and minute scales. 
Habits—The habits of this species are almost identical with those of 
Campostoma anomalum, with which in the north it is usually associated. 
It is, however, still more closely confined to the clear streams having 
their sources in springs. It is the most graceful of our minnows, and, in 
the breeding season, perhaps the most brillantly colored. In the 
aquarium, it is very hardy, and is altogether more desirable than any 
other of our species of Cyprinoids. This species seldom reaches a length of 
more than three inches. 
GENUS 27. HYBOGNATHUS. Agassiz. 
Hybognathus, AGassiz, Am. Journ. Sci. Arts, 1855, 223.—GiIRARD, Proc, Acad. Nat. Sei., 
Phila., 1856, 176, 180. 
Type, Hybognathus nuchalis, Agassiz. 
Etymology, hubos, gibbons; gnathos, jaw, the tip of the lower jaw having a slight pro- 
tuberance. 
Body more or less elongate and compressed ; mouth horizontal; jaws normal, rather 
sharp-edged, the symphyeis prominent; no barbels; upper jaw protractile; teeth 4-4, 
cultriform with an oblique grinding surface and scarcely any hook; alimentary canal 
elongated, about four times length of body; peritoneum black; scales large; lateral 
line continuons; dorsal over ventral; anal basis short; size moderate. 7 
Species numerous, the typical and largest one found in most streams east of the | 
Rocky Mountains, the others.mostly southwestern. 
50. HyBc@NATHUS NUCHALIS Agassiz. 
Silvery Minnow. 
Hybognathus nuchalis, AGassiz, Amer. Journ. Sci. Arts, 1855, 223.—JORDAN, Man. Vert., 
2d Ed., 1876, 289, and of many authors. 
Hybognathus argyritis, GiRARD, Proc Acad. Nat. Sci. Phila, 1856,-—-; U. S. Pac. R. R. 
Surv., x, 1859, —.—Copr, Proce. Am. Philos. Soe , 1870, —.—JORDAN, Man. Vert., 2d 
Kd., 1873, 289, and of most writers. 
Hybognathus evansi, GIRARD, Proc. Acad. Nat. Sci. Phila., 1856, —. 
Hybognathus regius, GERARD, Proc. Acad. Nat. Sci. Phila., 1856, ——JorDaAN, Man. Vert., 
2d Ed., 1876, 289. 
Hybognathus osmerinus, COPE, Proc. Am. Philos. Soc., 1870, —. 
Description.— Body elongate, comparatively slender; head moderate, rather short, the 
front comparatively steep; eye large, rather longer than the muzzle, about four in 
head ; upper jaw heavy ; lower jaw thin ; scales large and silvery ; lateral line decurved ; 
about twelve large scales in front of the dorsal; olivaceous green above, transluvent in 
life; sides clear silvery, with bright reflections; fins unspotted ; head 44; depth 44; D. 
8; A.1; teeth 4-4; lat. 1.38. Length, 5 to 7 inches. 
