B.—SYNOPSIS OF THE FRESH-WATER SILURIDA OF THE 
UNITED STATES, 
The nomenclature of the Silwride of our fresh waters has been for a 
long time in a very unsettled state, owing to the accumulation in our 
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 Siluride 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 Amiurus nigrilabris, Amiurus mispilliensis, and Amiurus niveiventris 
weredrawn 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 
to showing especially those characters which I consider to be specific 
in our Siluride, 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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