GILL] NOTEWORTHY EXTRA-EUROPEAN CYPRINIDS 309 
been revived by recent authors for the species. The latter name 
was given because the type specimens were found about Niagara 
Falls; its favorite resorts are also indicated by the name, for it 
largely resorts to rapids and swift running streams. 
A characteristic eastern American genus named Hybognathus has 
been referred to the Chondrostomines because it has an elongated 
alimentary canal (three to ten times as long as the body), but other- 
wise it is not like the typical members of the group. The jaws are 
Fie. 55.—Hybognathus nuchalis. After Fowler. 
sharp-edged and without corneous coverings and the pharyngeal 
teeth are uniserial (4—4), cultriform, and nearly straight. The 
gudgeon of the vicinity of Washington is the type of the genus. 
That type (Hybognathus nuchalis) is a fish with large scales, often 
about six inches long, of an olivaceous green color, with silvery 
sides and almost translucent. This style of coloration has also 
gained for it the name of smelt. It is much angled for from the 
wharves and shore-walls of Washington and is also used for bait. 
There are a couple of genera well marked as such, but otherwise 
possessing no salient external peculiarities that arrest immediate 
attention, which on closer examination are discovered to have quite 
exceptional characters; they have been named Campostoma and 
Exoglossum. Both of them were set apart many years ago (in 1866) 
by E. D. Cope as the types of independent sub-families which he 
named Mesocysti and Cochlobori, but for which those of Cam- 
postominz and Exoglossinz have been substituted by later American 
ichthyologists. 
The Campostomines, although having a somewhat peculiar physi- 
ognomy, present no external features which would lead one to 
