DESCRIPTION OF 
Remarks.—Many years since Prof. Ravenel sent me several specimens of this species 
under the name of S. campestris, (Say.) It does not, however, answer entirely to Say’s de- 
scription, and it certainly is not the same species with those placed in the Philadelphia 
Museum under that name by him. It is a more inflated species. It is quite white, with 
a few semi-transparent longitudinal lines. The aperture is about three-fourths the length 
of the shell. 
PLANORBIS. (Lamarcx.) 
Seventeen species of the genus Plunorbis have been described as inhabiting the waters 
of the United States, and I now propose to add three to that number. Lamarck described 
twelve, of which eight inhabit Europe. 
PLANORBIS REGULARIS. 
Testd subglobosd, superné subpland, subtus angusto-umbilicatd, pellucidd, pallido-luted, obsolete striata; anfracti- 
bus ternis, superné carinatis; labro acuto, marginato, intus incrassato; apertura ovata. 
Shell subglobose, above nearly flat, beneath narrow umbilicate, pellucid, pale yellow, obsoletely striate; whorls three, 
above carinate; lip acute, margined, within thickened; aperture ovate. 
Hab, United States. My Cabinet and Cabinet of P, H. Nicklin, Diam. .30, Length .20 of an inch. 
Remarks.—I have unfortunately mislaid the label which accompanied the shells from 
which the above descriptions were made. My impression is that they came from one of 
the Western States. All the specimens before me are very much alike in size and form, 
being exceedingly regular. The strie are more perceptible around the umbilicus and on 
the spire. On the side they are so much obliterated as to permit the whorl to present a 
shining appearance. The carina is very sharp and well defined. It has very much the 
appearance of a young ¢rivoluis, (Say,) and may possibly be only a variety of that species. 
PLanorsBis BucHANENSIS. 
Testa sublenticulari, superne subconvexd, ad peripheriam carinatd, subtus angusto-umbilicatd, vel corned vel sub. 
fused, levi; anfractibus ternis ; labro acuto; apertura rotunda. 
Shell sublenticular, above subconvex, carinate at the periphery, beneath narrow umbilicate, horn-colour or brownish, 
smooth; whorls three; lip sharp; aperture rounded. 
Hab. Near Cincinnati, Ohio. R. Buchanan. My Cabinet, and Cabinets of T. G, Lea, and R. Bu- 
chanan. Diam. .12, Length .08 of an inch. 
Remarks.—Several specimens of this species were sent to me several years since by my 
brother T. G. Lea, who informed me that they were first observed by Mr. Buchanan, after 
whom I name it. This species is very nearly allied to P. /ens,* nobis, but it may at once 
be distinguished by its round aperture, which is somewhat spread out. ‘The aperture of 
the lens, (now lenticularis,) is triangular, and the size of the shell rather larger. 
PLANORBIS BELLUS. 
Testé orbiculari, superné plano-concavd, subtus lato umbilicatd, virido-luted, crebrissime et elegantissime striata; an. 
fractibus quaternis, superne carinatis, subtus subcarinatis; labro acuto; apertura parva, subrotundd, intus rufo-fusca, 
Shell orbicular, above regularly concave, beneath widely umbilicate, greenish yellow, closely and beautifully striate ; 
whorls four, carinate above, subcarinate below; lip sharp; aperture small, within reddish brown. 
Hab. Tennessee, Dr. Troost. My Cabinet, and Cabinet of Dr. Troost. Diam. .40, Length .22 of 
an inch. 
* This name being preoccupied, I propose to change it to lenticularis. 
