HELIX. 49 
HEL'CION. Montf. Genus composed of species of Parexya, 
Auct. of an oval shape, with the apex distinctly and prominently 
bent forwards. 
HE’LENIS. Montf. A genus of microscopic Foraminifera. 
HELICINA. Lam. Fam. Colimacea, Lam. Ellipsostomata, Bl. 
Deser. Sub-globose, heliciform, rather thin; aperture sub-trigonal ; 
outer-lip thickened and reflected, inner-lip spread over the body 
whorl, terminating in a point. Operculum testaceous, triangular, 
concentric. Obs. This genus, distinguished from Helix by having 
an operculum and a thickened columellar lip, consists of several 
pretty little recent species found in the West Indian, S. Sea and 
N. American islands. Fig 306, H. Major. 
HELICITES. Bl. Part of the genus Nummuurres, Lam. 
HELICOLIMAX. Fer. Virrina, Drap. H. Pellucida, fig. 263. 
HELIXA’RION, Fer. Virrina, Drap. Differing from Helicoli- 
max in the structure of the animal. Fig. 262. 
HELIX. Auct. Fam. Colimacea, Lam. Descr. Orbicular, light, 
generally globular; spire short, last whorl ventricose, aperture 
oblique, peritreme reflected, interrupted by the most prominent 
part of the body whorl; columella confluent with the outer lip. 
and contiguous to the axis of the shell. No operculum, a thin 
epidermis. Obs. The land shells composing this genus are found 
in all parts of the world, the common snail, H. Aspersa, is well 
known as a destructive animal in our gardens. The genera 
Helix, Achatina, Bulinus, Clausilia, Anostoma, &c. have been 
united under one generic name by De Ferussac, and again divided 
under the following sub-generic names, each of which we shall 
illustrate by a figure. Genus Hexix: Sub-genus 1, Helicophanta, 
consisting of species with large apertures, like Vitrina; Helix 
brevipes. SS. gen. 2, Cochlohydra, Succinea Amphibia, Drap. 
S. gen. 3, Helicogena, consisting of the common species with the 
last whorl large; Helix Hemastoma, H. Contusa, (Streptaxis, 
Gray,) H. Aspersa. S. gen. 4, Helicodonta, consisting of species 
with teeth or folds onthecolumella; Polydonta, Montf. Anostoma, 
H. Nuxdenticulata. S. gen. 5, Helicigona, Carocolla, Geotrochus. 
S. gen. 6, Helicella, consisting of depressed species with a large 
umbilicus; H. citrina, (Naninia, Gray.) 8S. gen. 7, Helicostyla, 
consisting of species with a simple aperture like the Helicogene, 
but with the whorls increasing very gradually. H. epistylium. 
S. gen. 8, Cochlostyla, Bulinus, SS. gen 9, Cochlitoma, Achatina. 
S. gen, 10, Cochlicopa, Polyphemus Glans. S. gen. 11, Cochlicella, 
Bulinus decollatus. S. gen. 12, Cochlogena, Azeca tridens. S. gen. 
13, Cochlodonta, Pupa Uva. S. gen. 14, Cochlodina, Clausilia 
macascarensis, Balea fragilis. The last three sub-genera are in- 
cluded in the genus Odostomia of Fleming. We give an example 
of each of these sub-divisions, for the sake of presenting the 
H 
