258 Comparative elevation of Testacea in the Alps. 
VITRINA, nov. sp. F. glacialis, Mihi. 
Testa hyalina, supra plana, spi- 
ris duobus ; apertura patentissima, 
ovato-oblonga. Long, j poll. Lat. 
J. Animal nigrum ; capite, cauda, 
tentaculisque obtusis. 
I found this beautiful and very distinct species of Vitrina in con- 
siderable plenty under stones on the high elevations referred to, and 
only there. Ferrussac figures two alpine species, the V. annulata, 
" Venetz," and the V. pyrenaica, both of which appear to be varie- 
ties of V. pellucida, and far removed from the V. glacialis, the 
nearest ally of which is perhaps the V. elongata of Draparnaud : 
but the animal of V. elongata is grayish- white, a distinction suffi- 
ciently specific, independent of the comparative characters of the 
shells. The V. glacialis seems to have escaped the observation of the 
Swiss conchologists Thomas and Studer, neither of whom refer to 
any other species in their catalogues, besides V. pellucida and V. 
elongata. Few indeed would think of searching for shells in such 
an icy habitat as that of the V. glacialis. 
Helix arbuslorum, var. alpina, Ferr. 
This dwarf variety is found abundantly at about the same elevation 
with the Vitrina, and ceases in the following zone. 
II. At Swaribach on the Gemmi and similar elevations, never 
very close to the snow masses. Plants Nigritella angustifolia, 
Polygala chamaebuxus, &c. 
Bulimus (Cionella) lubrica, var. alpina. 
A very pretty and curious variety of this species, distinguished 
from the normal form by its dwarf size, more contracted mouth, and 
whitish colour. 
Pupa secale, Drap. 
cylindrica, Ferr. 
marginata, Drap. 
Clausilia with the shell tapering, almost smooth : mouth with a 
single^primary tooth and an obsolete secondary fold. Var. of C. 
minima, Pfeiffer? 
Helix rupestris, Drap. 
crystallina, Drap. 
trochilus, Mont, (fulva, Mull.) 
nitida, Mull. 
In springs on the Faulhorn at the same elevation I found Lym- 
naea fossaria, (3. minuta, Drap. an Cyclas (Pisidium) obtusale, Pfeiff ? 
III. The dwarf pines appear. All the species mentioned under 
II. are found in this and the following zone, with the exception of 
