KENNARD AND WOODWARD : MOLLUSCA OF CAVE-DEPOSITS. 243 



VaUonia piiJchella, Miill. Claimlia laminata, Mont. 



Uelicigoua lapieida., Linn. CocJiIicopa luhrica, Miill. 



,, arhmtoruDi, Linn. Ccecilianella acicula^ Miill. 



Helix nemoralis, Linn. Succinea ohlonga, Drap. 



,, hortensifs, Miill. Carychium minimum, Miill. 



Pupa muscorum, Linn. Pomatias elegans^ Miill. 



Vertif/o minutissima, Hart. l/uio, sp. 

 Clausilia hidentata, Striim. 



It will at oncG be noticed that the species from the Devon cavern 

 also occnr at Ightham, but their number is so small that a true 

 comparison is not possible. It is interesting, however, to note that 

 Pomatias elegans and Vifrea alliaria are unknown from any of the other 

 Pleistocene deposits in this country, althougli prcisent in the Holocenes 

 of Essex. In a MS. of the late Dr. 8. P. Woodward, the former shell 

 is recorded from Kent's Cavern. This is pi-obably correct, thougli no 

 examples are known to exist. Many of the shells from both localities 

 retain some of their coloration, but the Ightham examples arc by far 

 the better preserved. This fact has been used as an argument against 

 their presumed age. The condition of a fossil does not, however, depend 

 on its age (the Eocene shells of the Paris Basin being noteworthy 

 examples), and the tine preservation of these fissure shells arises from 

 tlie exceptional conditions under which they were preserved. 



In the Happaway Cavern, Pomatias elegans is the commonest form, 

 Vitrea cellaria coming second, whilst V. alliaria, Helicclla caperata, and 

 Helix horteims are represented by single examples only. With the 

 Ightham shells, Vitrea cellaria is the most abundant, several hundred 

 examples of all ages having passed through our hands. Its prevalence 

 is perhaps accounted for by the fact that at the present day it is 

 largely a cave-dweller. Agrioliinax agrestis and Vitrea radiatula are 

 only known from solitary specimens. 



Vitrea Helvetica, Blum., is the British shell commonly known as 

 V. glabra, iStud. We have, however. Dr. Westerlund's authority for 

 this change of name, and there can be no doubt that our shell differs 

 from Htuder's species. Two examples have been found. It has 

 hitherto never been recorded fossil in this country. 



llygromia ionhrosa, Partsch, is by far the most noteworthy form, 



/ 

 f 



^;:. .-• ■■/ I 





llijfironiia nuihrosa, Partsch. x 2h. 



since it has not been met with previously on this side of the Channel. 

 Its present range is Southern Germany, Bohemia, Switzerland, Silesia, 



