APPENDIX.
265
on the margin exhibiting the bands distinctly; labrum simple, as much rounded above as below; umbilicus small, nearly closed.
Greatest width one inch and nine-twentieths.
Total length one inch and a half.
Length of the aperture one and one-fifth of an inch nearly.
Inhabits East Florida.
During an excursion to East Florida, in company with Messrs. Maclure, Ord, and T. Peale, I obtained a single dead and imperfect specimen of this interesting shell. It occurred in a small creek, tributary to St. John's river, and on the plantation of Mr. Fatio. Captain Le Conte of the Topographical Engineers, has since presented me with a perfect specimen, with the information that he observed them in very great numbers on the shores of Lake George, a dilatation of St. John's river; that in some places the dead shells were piled up confusedly to a considerable height, and that the Numenius longirostra feeds upon the living animal. The spire is still less elevated than that of the globosa of Swainson. PL 14, fig. 2.
MELANIA.
M. virginica, nob. Falls of Niagara.
ANODONTA.
A. gibbosa. Shell thin and very fragile; much inflated; anterior and posterior hinge-margins compressed, the former alated; surface pale-yellowish testaceous, finely radiate with green, and having somewhat regular concentric minute undulations; within somewhat iridescent.