( 45 ) 
GENUS HELIX. (1) FERUSSAC. 
SUB-GENERA. 
A. Horizontally volute, 
4, Heuicocena. Fer. 
Globulous or elliptical ; Umbilicus masked. 
peristoma simple. 
a Collumellate. Columella solid and twisted. Pl. 7, fig. 7, 8. 
6 Acave. Umbilicus entirely covered by an expansion of the columella, 
Pl.7, fig. 44544: 
c Perforate. Umbilicus appearing in part, like a cleft, behind the expan- 
sion of the columella. Pl. 7, fig. 9, 10 
d Imperforate. Depressed, umbilicus closed. Pl. 7, fig. 15, 16, 18. 
2. Heticoponta. Fer. 
More or less globulous Mouth generally tooth- 
and depressed ; peristoma ed in the perfect state. 
reflected or thickened. 
a Personate. Peristoma sinuous and thick; or reflected with teeth, plates, 
or folds. Pl. 7, fig. 17. 
6 Lamellate, Mouth with one or more elongated internal plates. Pl. 7, 
ip. 495 a, 6, c,d, ¢. 
e Maxillate. Peristoma with large teeth; a gutter at the base of the co- 
lumella, Pl. 7, fig. 21, 
d Anostomz. Tomogeres, Montf. Mouth reversed or dorsal, with elevated 
folds or teeth. Pl. 7, fig. 20. 
e Impresse. Inner lip with longitudinal elevated folds. Pl, 7, fig. 23. 
3. Hexicicona. Fer. Ca- 
RACOLLA. Lam. 
Carinated, somctimes 
conical. ; 
a Caracollx, Umbilicus covered. Pl. 7, fig. 22; pl. 8, fig. 1, 2. 
6 Vortices, Ocken. Umbilicus masked or visible. Pl. 8, fig. 3. 
4. Henicetra. Fer. VYor- 
TEX. Ocken. 
Elliptical or flattened. Umbilicus exposed. 
a Lomastome. Peristoma reflected. Pl. 8, fig. 8. 
6 Aplostome. Peristoma simple. Pl. 8, fig. 4. 
e Marginate. Peristoma margined, Pl, 8, fig. 5, 7,18. 
(1) Fide p. 30, 
