FAMILY 2. PERISTOMATA. 1351 
as it merely exhibits a modification of the bispirate character common to 
the rest of the Ampullarie. 
The shell of Ampullaria may be described as being globose, or globosely 
discoidal, and covered with an olivaceous epidermis ; the spire is small, 
and rather sharp, and the whorls are ventricose, the last being unusually 
large, and forming an umbilicus ; the aperture is entire, generally oblong, 
and angularly acute at the upper part ; the margin is continuous, and the 
lip, which is somewhat thickened, is sometimes a little expanded, but 
never reflected. 
The Ampullariz are most abundant in warm climates. 
Examples. 
Pl. CXCVIII. Fig. 1 and 2. 
AMmPULLARIA RUGOSA (2), Lamarck, Anim. sans vert., new edit., vol. viil. 
p. 532. Chemnitz, Conch., vol. ix. pl. 128. f.1136. Encyclopédie 
Méthodique, pl. 457. f. 2.a, b. 
Nerita urceus, Miiller. 
Bulimus urceus, Bruguiére. 
Ampullaria urceus, De Férussac. 
Pl. CXCVIII. Fig. 3. 
AMPULLARIA CORNU ARIETIS, Sowerby, Genera of Shells, No.4. Ency- 
clopédie Méthodique, pl. 460. f. 3. a, b. 
Heh cornu arietis, Linnzus. 
Planorbis contrarius, Miller. 
Planorbis cornu arietis, Lamarck. 
Ceratodes fasciata, Guilding. 
Ceratodes cornu arietis, D’Orbigny. 
Pl. CXCVIII. Fig. 4. 
AMPULLARIA SUBCARINATA, Sowerby, Genera of Shells, No. 4. 
Lanistes ———— ? De Monttford. 
32 
