MOLLUSCA. PULMONIFERA, 
255 
PULMONIFERA. 
TERRICOLA. 
Tentacula usually round, and four in number. The eggs are 
hatched on land. 
I. LiMACiDiE. Cloah and foot ^parallel, enclosing the viscera. 
a. Pulmonary cavity placed near the head, covered by a thick shield. 
Arion 
Limax. 
aa. Pulmonary cavity near the tail, covered by a spiral open shell. 
Testacella. 
II. CocHLEADiE. Cloah and foot not parallel; the viscera con- 
tained in a spiral, dorsal protuberance, protected by 
a shell. 
a. Foot with a lid for closing the mouth of the shell. 
Cyclostoma. 
Helecina. 
aa. Foot destitute of a lid. 
h . Helicida;. Last formed whorl larger than the penultimate 
one. 
c. Animal capable of retiring within the shell, the peristome of 
which, with the exception of Achatina, becomes thick at 
maturity.^ 
d. Shell depressed or globose. 
e. Peristome entire, raised on the pillar. 
Carocolla. 
ee. Peristome inten-upted on the pillar. 
Helix. 
dd. Shell turrited. 
Bulimus. 
Achatina. 
cc. Animal incapable of withdrawing within the aperture of the 
shell, the margin of which is thin. 
Succinea. 
Vitrina. 
bb. PuPADA. Last formed whorl nearly of the same size as the 
penult one, or even less, giving the shell a subcylindrical 
form. 
c. Whorls dextral 
Pupa. 
Azeca. 
Carychium. 
cc. Whorls sinistral. 
Balea. 
Clausilia. 
Vertigo, 
