The Food of the Smaller Fresh - Water Fishes. 
75 
mentary canal, in the former the teeth are usually sharp-edged or 
hooked, in the latter truncate, hammer, or spoon-shaped.” 
“In the American genera, as far as included in the scope of 
this essay, the peculiarities of the intestines correspond with the 
food. In the Alburnellus rubrifrons ,* they are but four-fifths the 
length of head and body (excluding caudal fin). In Hypsile- 
pis Jcentukiensisf Photogenis leucops , Argyreus atronasus 3 and 
nasutus , 3 Ericymba buccata , and Exoglossum maxil lingua, about 
seven-ninths; the food of the last five species is insects and crus- 
taceans, the last depending largely on mollusca. In the species 
of Ceratichthys, Semotilus, and Hybopsis, with JFFypsilepis cor- 
nutus , 4 fifteen-sixteenths to equal the length; the habits insectiv- 
orous. The genera with longer intestines are, first, Stilbe 5 one and 
two-fifths to one and three-fourths the length; Chrosomus, Hybor- 
hynchus, and Pimephales two and two-fifths to two and two-thirds, 
and Hybognathus four times. The intestines in these are gener- 
ally filled with a soft, dark-colored slime, without remains of 
insects, but of vegetable origin. In the remarkable genus 
Campostoma the canal extends to between eight and nine times 
the length, and, like that of other vegetable feeders, is usually 
found occupied by the ingesta for a considerable part of its 
length.” 
This statement is in the main correct as far as it goes, but it 
will be seen from the following data, and from the discussion of 
the food of the family, that it is far from the truth with respect to 
the genus Campostoma and its allies. 
If we examine the alimentary structures of the Cyprinidm, to 
which reference has been made in describing the food of the pre- 
ceding families, we shall find these fishes easily divided into at 
least four tolerably distinct groups, defined by characters drawn 
from the gill-rakers, the pharyngeal teeth and the intestines. In 
all but two of the genera of this paper* the gill-rakers are short 
and insignificant. The pharyngeal teeth may be either hooked or 
plain, and with or without grinding surface, while the intestine 
varies in length from less than that of the body without the head 
’Minnilus or Notropis. 2 Photogenis analostanus. 3 Rhinichthys. 4 Lux- 
ilus cornutus. 6 Notemigonus. 
:I T have used here, for convenience’ sake, the nomenclature of the 
Catalogue of the Fishes of Illinois, published in our third bulletin. 
