CONTRIBUTIONS 
NORTH AMERICAN ICHTHYOLOGY. 
No. 2. 
A.—NOTES ON COTTIDH, ETHEOSTOMATIDA, PERCIDA, CEN- 
TRARCHIDA, APHODODERIDA, UMBRIDA, ESOCIDA, 
DORYSOMATIDA, CYPRINIDA, CATOSTOMIDH, AND HY- 
ODONTIDA, WITH REVISIONS OF THE GENERA AND 
DESCRIPTIONS OF NEW OR LITTLE KNOWN SPECIES, 
COTTIDA. 
1. COTTOPSIS SPILOTUS, (Cope) Jor. 
Uranidea spilota, Corr, Proc. Ac. Nat. Sci. Phila. 1865, 82. 
Cottopsis ricei, NELSON, Bull. Ills. Trans. Nat. Hist., 1876.—JORDAN, Proc. Ac. Nat. Sci. 
Phila. 1877, 61. 
An examination of the types of U. spilota shows their probable iden- 
tity with Mr. Nelson’s species as above indicated. Prof. Cope’s speci- 
mens are in bad condition, and have lost the peculiar dermal spines. 
Prof. Gill thinks that Cottopsis spilotus and Cottopsis semiscaber Cope 
are not truly Cottopsis, the only species properly referable to that genus, 
being C. asper Rich. (of which C. parvus Grd. is the young). At any 
rate, C. spilotus and C. semiscaber form a well-marked group or section 
intermediate between Cottopsis and Potamocottus. 
ETHEOSTOMATID. 
2. AMMOCRYPTA BEANILI, gen. et sp. nov. 
Generic characters.—Allied to Pleurolepis Agassiz. Body greatly 
elongated, subcylindrical, and translucent. Head as in Plewrolepis, but 
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