a 
L. Agassiz on the Ichthyological Fauna of Western America. 89 
I know four distinct species of this genus from personal exam- 
ination, all well described and figured by Lesueur and Dr. Kirt- 
land, viz: Catostomus Aureolus, Les., Catost. Duquesnii, Les., 
vatost. macrolepidotus, Les., and Catost. melanops, Rafin. The 
Catost. Sueurii, Rich., Fauna Boreali-Americani, I have not seen 
myself, nor the Catost. Carpio, Vad., but from their description, and 
from the figure given of the latter by Valenciennes, I am inclined 
to believe that Cat. Sueurii is founded upon the male of Catost. 
Duquesnii. It cannot be a distinct species, since three species only 
of this genus are found within the natural boundaries of the fresh- 
water fauna of New York :—Catost. aureolus, Catost. Duquesnii, 
and Catost. macrolepidotus, one of which, C. aureolus, 
has himself accurately described. Rafinesque’s Catostomus eryth- 
rurus is identical with Lesneur’s Cat. Duquesnii. As to Catosto- 
mus melanops, Raf., it is a well characterised species, which Dr. 
Kirtland has for the first time satisfactorily described; but the 
Species Valenciennes described afterwards under the name of C. 
fasciatus from specimens sent him by Lesueur under that name, 
18 synonymous with it, as is also his own Cat. melanotus. Judg- 
ing from the form of the anal, and the position of the dorsal, I 
believe that Catostomus insignis, B. § G., which I have not seen, 
also belongs to this genus, though no mention is made in their 
description of the character of the lips, so important in this tribe, 
as Lesuetr has already shown. he black dot at the base of 
each scale, brings it near Ptychostomus melanops. 
_ The geographical distribution of these species presents some 
Interesting peculiarities ; for three of them, C. aureolus, Duques- 
nit and macrolepidotus are found in the Canadian Lakes, and yet | 
they do not cover the same areas, C. aureolus, extending chiefly 
northwards, Catostomus Duquesnii westwards, and C. macrolepi- 
dotus eastwards ; C. mela on the contrary, is only found in 
the West and Southwest, and not in the great Lakes. If, upon 
close examination, Catostomus insignis should prove to belong 
to this genus, it would furnish additional evidence that the Pty- 
chostomi with dotted seales are the southwestern type of the 
genus, 
Stoonp Sznims, Vol. XIX, No, 65—Jan. 1855. 12 
