120 
ST. HELENA. 
guished by its size, being the largest of all the species. It is still 
found alive in considerable numbers, feeding upon the cabbage trees, 
tree ferns, and native vegetation generally in the damp, cool 
region on the bigli central ridge, at an altitude of 2600 feet above 
the sea. 
Zonites, Gray. 
Z. cellar ius, Mull. — This native of the British Isles has 
probably been introduced through the agency of the earth contained 
in Ward’s cases of plants. It is easily recognised, being a small, 
flat, spirally-formed snail, very abundant in gardens, where it assists 
the common garden snail with its voracious aptitude for the destruc- 
tion of young vegetation. 
Z. alliarius, Miller. — Another British species, found commonly 
associated with the other. 
Helix, Linn. 
H. aspersa, Mull. — This world-wide distributed creature, the 
Common Garden Snail, is abundant all over the Island, and has, 
without doubt, been introduced in the earth contained in Ward’s 
cases of plants. It exists in large numbers on the somewhat barren 
plains of Longwood and Prosperous Bay, where it finds a cool and 
moist atmosphere as well as food amongst the creeping plants of 
the Hottentot Fig {Mesem hryan th em am edule). In the hot season, 
when those plants partially die away, the empty snail-shells may be 
gathered from beneath them by hundreds. 
*H. polyodon, G. B. Sow.=H. Alexandri, Forb. — A small 
shell now found, together with the following five species, all of which 
are natives of the Island, in a subfossil state, embedded in the 
surface-soil on the north-eastern quarter of the Island, at an altitude 
above the sea of 1200 to 1500 feet. Described and figured 
“ Proceed. Geol. Soc.,” March 10, 1852, p. 19S, pi. v. f. 9 ; also in 
Mr. Darwin’s work on Volcanic Islands. 
*H. helenensis, Forb. — A small, round, whitish-brown, 
spirally-formed shell, of a Pacific type, from the roadside banks on 
Side-Path above The Briars. 
*H. cutteri, Pfr. — A smaller species than the last, but found 
associated with it. 
*H. spurca, G. B. Sow. — From near Flagstaff Hill ; altitude 
above the sea 1 600 feet. Described in the appendix to Mr. Darwin’s 
