ON THE SPECIES OF THE GENUS ANOSTOMUS. 



BY S. GAKMAN. 



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 ScJiizodontopsis 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 



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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 mandibular teeth are short, 

 broad, and crenulated. This section includes the six re- 

 maining species. The characters assigned ScMzodon sag- 



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