P, sinistrosa.* 
P. Nuttaliana.* 
P. virens.* 
P. pallida.* 
P. subcarinata.* 
P. genicula.* 
P. magnifica.* 
P. limosa.* 
P. subglobosa.* 
P. lapidaria.* 
P. Virginica.* 
CONCHOLOGY. 
113 
P. hyalina.* 
P. unicolor.* 
P. nuclea.* 
P. decisa.* 
P. fuscus.* 
P. dissimilis.* 
P. ponderosa.* 
P, integra.* 
P. porata.* 
P. lustrica.* 
P. grana.* 
P. Nickliniana.* 
3. Genus Ampullaria. Pl. X. 
Animal. Inflated, globular, spiral; foot oval, with a trans- 
verse furrow at its anterior edge; head wide; tentacula superior, 
very long, conical, and pointed; eyes situated at their external 
base, and supported upon a very apparent peduncle; mouth ver- 
tical, situated between two lips disposed in form of a horse shoe 
and forming a kind of muzzle; no superior tooth; a bristly lingual 
band, but not prolonged into the abdominal cavity; a very large 
respiratory cavity, divided in two by an incomplete horizontal 
partition. 
Animals of this genus are oviparous; producing an egg nearly 
as large as that of a pigeon, in which is found the young animal 
complete, and in a perfectly formed shell. 
Shell. This genus appears to partake of the characteristics, 
both of the Paludina and the Natica, being fluviatile and fre- 
quently attaining a large size; spire very short, the last whorl 
much larger than all the others together; globular, very ventri- 
cose, umbilicus small, forming a compressed funnel-shaped aper- 
ture, without interior callosity ; aperture'longer than broad, with 
margins united; columellar lip thickened, projecting and reflected. 
over the umbilicus; operculum horny. Inhabits the rivers of 
Europe. Thirteen species. 
Ampullaria vivipara. 
A. fasciata. 
Ampullaria rugosa. 
A. canaliculata. 
10* 
