tiles


Note:  Do not rely on this information. It is very old.

Operculata

Operculata, a group of land shells which are distinguished by the possession of a hard plate, which closes the mouth of the shell, similar to that of many marine gastropoda (q.v.), such as the periwinkle (Littorina littorea). The only English species is Cyclostoma elegans, which is common in limestone districts in the south of England.