838 FISHES — 



Habitat, Ohio Valley to Red River of the North, ia 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 

 Camposioma 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 Oyprinoids. This species seldom reaches a length of 

 more than three inches. 



Gbnus 27. HYBOGNATHUS. Agassiz. 



Hyhognaihue, Agassiz, Am. Journ. Sci. Arts, 1855, 223. — Girard, Proc. Acad. Nat. Sci., 

 Phlla., 1856, 176, 180. 

 Type, Hyhognathus nuchalis, Agassiz. 



Etymology, huhos, gibbons ; gnathos, jaw, the tip of the lower jaw having a slight pro- 

 taberance. 



Body more or less elongate and compressed ; mouth horizontal ; jaws norma), rather 

 sharp-edged, the symphysis prominent; no barbels; upper jaw protractile ; teeth 4-4, 

 oultriform with an oblique grinding surface and scarcely any hook ; alimentary canal 

 elongated, about four times length of body; peritoneum black; scales large; lateral 

 line continnous ; dorsal over ventral ; anal basis short ; size moderate. 



Species numerous, the typical and largest one found in moat streams east of the 

 Kocky Mountains, the others mostly southwestern. 



50. Hybjgnathds nuchalis Agassiz. 



Silvery Minnow. 



Hyhogvathua nuchalis, Agassiz, Amer. Jonrn. Sci. Arts, 1855, 223. — Jordan, Man. Veit., 



2d Ed., 1876, 289, and of many authors. 

 Sybognathua arggritis, Girard, Proc. Acad. Nat. Sci. Phila , 1856, — ; U. S. Pac. R. R. 



Snrv., X, 1859, — . — Cope, Proc. Am. Philos. Soc , 1870, — .—Jordan, Man. Vert., 2d 



Ed., 1878, 289, and of most writers. 

 Hyiognatkns evaiisi, Girard, Proc. Acad. Nat. Sci. Phila., 1856, — . 

 Hyiognathuaregius, Girakd, Proc. Acad. Nat. Sci. Phila., 1856, — — Jordan, Man. Vert., 



2d Ed., 1876, 289. 

 Syhognathus osmerimw. 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 mnzzle, about four in 

 head ; upper jaw heavy ; lower jaw ihin ; scales large and silvery ; lateral line deonrved ; 

 abont twelve large scales in front of the dorsal ; olivaceous green above, translucent in 

 life ; sides clear silvery, with bright reflections ; iins unspotted ; head 4^ ; depth 4J; D. 

 8 ; A. 1 ; teeth 4-4 ; lat. 1. 38. Length, 5 to 7 inches. 



