ON THE SPECIES OF THE GENUS ANOSTOMUS. 
BY S. GARMAN. 
The characteristics of the various fishes credited to it 
are such as to divide the genus Anostomus into three com- 
paratively distinct groups or subgenera. The large series 
collected by the Thayer Expedition for the Museum of 
Comparative Zoology illustrate this to advantage, and at 
the same time they furnish several types that do not ap- 
pear to have previously been noticed by ichthyologists. 
The first of the groups {Anostomus) is characterized by 
an elongate narrow snout, of which a cross section in 
front of the eyes would be nearly round, by a mouth turned 
almost directly upward and by long, .slender, crenulate 
mandibular teeth. It contains but two of the species. 
The second group, to which the name Sclnzodontojjsis is 
given, is marked by a short broad snout, of which a trans- 
verse section behind the nostrils would be sub-elliptical ; by 
a mouth turned obliquely upward and forward, and by 
teeth on the mandible that are broad and truncate, having 
entire or chisel-shaped edges. Four species of close affin- 
ities are to be included in this group. The third of the 
sub-genera (Schizodon) is similar to the second in shape of 
snout, but the mouth is directed forward or, in one species, 
obliquely downward, and the mandil)ular teeth are short, 
broad, and crenulated. This section includes the six re- 
maining species. The characters assigned Scliizodon sag- 
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