B. -SYNOPSIS OF THE FRESH-WATER SILURIDiE OF THE 

 UNITED STATES. 



The nomenclature of the Siluridce of our fresh waters has been for a 

 lonj,' time in a very unsettled state, owing to the accumulation in onr 

 descriptive works of a large number of nominal species, and to the 

 general lack of sharp characterizations in the published descriptions. 



The writer has attempted to go over the subject critically, with a 

 view to ascertaining the basis on which each species rests, and to elimi- 

 nating all those whose claims to recognition are doubtful. I have 

 accordingly considered every nominal species as invalid, unless either 

 from the description itself or from the examination of specimens, some 

 differences apparently permanent could be appreciated. Some species 

 not here recognized will doubtless prove valid, but at least nine-tenths 

 of those not admitted are simply spurious, either based on individual 

 peculiarities of specimens, or more often on ignorance of species previ- 

 ously described. 



This paper is based primarily on the collections in the United States 

 National Museum. The writer has also examined most of the speci- 

 mens of Siluridce preserved in the Museum of the Academy of Natural 

 Sciences at Philadelphia. Most of the species here recorded are also 

 in the author's own collection, deposited in the Museum of Butler Uni- 

 versity at Indianapolis, Ind. 



The drawings accompanying this paper were nearly all made by Mr. 

 Ernest R. Copeland from specimens in the author's collection. Those 

 of Amiiirus 7iigrilahris, Amiurus mispilliensis, and Amiurns nivciventris 

 were drawn by Miss Belle Sherman from Prof. Cope's types in the Museum 

 of the Academy. A few others were drawn by Mr. Todd from specimens 

 in the National Museum. These drawings are to be considered rather 

 as illustrative diagrams than as pictures. They are drawn with a view 

 toshowiug especially those characters which I consider to be specitic 

 in our Siluridoc, viz. the general outline, the position of the dorsal fin, 

 the size, number of rays, and position of the anal fin, the form of the 

 caudal fin, and the size and form of the pectoral spines. These features 



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