52 Our British Snails 



Cyclostoma {Po^natias) elegans. — Common on 

 calcareous soils, especially chalk. A spiral shell 

 of 4j whorls, suture very deep. Mouth circular 

 (whence its name) and provided with a thick 

 shelly operculum which closes the orifice when 

 the animal retires by means of an elastic ligament. 

 This and the next species are our only land shells 

 provided with an operculum, and this shows their 

 derivation from the marine Gasteropoda (e.g. whelk 

 and winkle). Perhaps all shells were originally 

 marine, but some became first amphibious and 

 then terrestrial. It is quite unlike any other of 

 our land shells. 



Acicula lineata is a very small shell, the size 

 of the Pupae ; mainly northern in distribution. 

 Feeds on liverworts and fungi. Very local ; 

 6 or 7 whorls. Mouth pear-shaped, with a horny 

 operculum. 



The Family Succinea really ranks with the land 

 shells, as belonging to the sub-order Pulmonata 

 or lung-breathing molluscs. It is, however, 

 amphibious, and hibernates in the mud at the 

 bottom of a ditch. 



Succinea piUris (it is the mud, not the animal, 

 which is putrid !) is called the Amber Snail from 

 the colour of its shell, which is unlike any other. 

 Common on flags, etc., at the edges of ditches 

 and ponds. 



Succinea elegans. — Difiicult to distinguish from 

 the former, but the animal is darker and the shell 



