258 Comparative elevation of Testacea in the Alps. 



Vitrina, nov. sp. V. glacialis, Mihi. 

 Testa hyalina, supra plana, spi- 

 ris duobus ; apertura patentissima, 

 ovato-oblonga. Long, i poll. Lat. 

 i. Animal nigrum ; capite, eauda, 

 ientaculisque 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. 



Bidimus (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 



