606 Note on the Genus Campeloma of Rafinesque. [ June, 
tho. It is quite difficult to conceive of two species more widely 
separated from each other than the two this author makes illus- 
trative of Melantho. I know of no naturalist in America who 
would not unhesitatingly refer these shells to separate and dis- 
tinct genera. | 
Summing up the facts in the case of this neglected genus, it 
is certain that the shells constituting it cannot be referred to Pal- 
udina of Lamarck, and equally certain it is that Melantho of - 
Bowditch will not apply. There having been as yet no other 
generic name proposed but Campeloma for these mollusks, one 
Species of which was surely before Rafinesque in framing his 
diagnosis, the rules of priority, and justice alike, will necessitate 
its use, 
A word or two regarding the forms included in Campeloma may 
not be out of place. The genus has a wide distribution east of 
the Rocky mountains, occurring in nearly or quite all the States 
from Texas to Maine, to Minnesota and beyond into British 
America. The most widely distributed species of the group's 
Campeloma decisum Say, which is found throughout all the 
northern sections of this region, extending into Nova Scotia and 
far northward in the Province of Quebec; thus being the 
only species the distribution of which reaches beyond the term 
tory of the United States. It is the only form common in New 
England. In the western portion of this latter area appear 
another form, the Campeloma integrum DeKay, and in the ex- 
treme south-west of Connecticut the distinct form Campeloma 
rufum Haldeman, also occurs. The most western limit of pe 
last species appears to be the Cedar river in Iowa, from whi 
locality a single specimen has been placed in my cabinet. 7 
three species mentioned, decisum, integrum and rufum are r a 
associated in great numbers in certain parts of the State of ye 
York, notably in the Erie canal, and wherever so found pe 
their specific characters to a remarkable degree. Westward Ohio. 
New York, in Western Pennsylvania in the drainage o elop 
a fourth form occurs, which appears to reach its greatest es 7 
ment in that great waterway, the Campeloma pena o , 
reversed specimen of which form, as has been said, serve a Ne 
type of the genus. In the State of Ohio occurs a fifth Hs act 
Campeloma obesum Lewis, which seems to luxuriate 1 y per- 
waters of the central portions of the State. In Illinois, a. 
