I50 HELICID^. 



the shell by the slime of the animal, or perhaps by a 

 viscous exudation from the epidermis. 



Sometimes the disguise, instead of being formed of 

 mud, consists of minute lichens, the spores of which 

 have fallen upon and taken root in the epidermis of 

 the shell. 



This species owes its name ohsairiis (hidden) to 

 these facts, but it is not the only mollusc for which 

 this safeguard has been provided ; the young of the 

 last species, B. montaims, as well as those of Pttpa 

 secale, are often similarly encrusted with mud. 



Var. alba. — Shell white or colourless. Sevenoaks in Kent 

 (Smith), Lulworth, Dorset (J. G. J.), near Bristol (Miss F. M. 

 Hele), B.C. Near Croydon (R. R.). 



GENUS VL—PU'PA* LAMARCK, 



Body capable of being contained within the shell; tentacles 

 4, short, lower pair shorter than the upper ones ; foot narrow. 



Shell cylindrical ; who?' Is compact ; spire more or less pro- 

 duced ; mouth horseshoe-shaped or semi-oval, usually toothed, 

 sometimes provided with spiral plaits or folds ; wnbiliats 

 minute. 



These little snails are gregarious, and live among 

 moss and dead leaves, as well as upon rocks, beneath 

 the bark of trees, and under stones, both in low-lying 

 and elevated situations. They are herbivorous, and 

 some species are ovoviviparous. Pupa (from piLpiis) 

 is a Latin word which signifies a child, and also a 

 puppet or doll. It has been applied to these shells, 

 as well as to the chrysalis of insects, because of their 

 fancied resemblance to an infant in swaddling clothes. 



* A doll. 



