PELTELLA. 123 



Shell internal, oval, depressed, shining, transparent, sub- 

 spiral, olivaceous, with a large, white, spatulate lamella 

 developed, in the adult, from the fore part. 



Ex. C. ambigua, Ftrussac, pi. 72, fig. 5. Shell, C. 

 amhigua, fig. 5, a. 



In the very young animal, the shell is without the spatu- 

 late, lamelliform concretion in front, and is provided with a 

 thin, homy, convex operculum, which afterwards disappears. 

 The Gryptella is an inhabitant of the Canary Islands ; 

 during eight or nine months in the year their vital activity 

 is suspended, and they conceal themselves under the large 

 blocks of lava with which these islands are covered ; they 

 are herbivorous, and during the rainy season, especially in 

 the night, they quit their retreats and commit great havock 

 in the gardens. The peasants destroy them by thousands, 

 but, notwithstanding this persecution, their numbers do not 

 appear to diminish. 



Genus PELTELLA, Webb and Van Beneden. 



Animal limaciform, depressed. Mantle appendiculate 

 on the right side under the spire ; orifice of respiratory sac 

 at the right posterior margin. Foot flattened, dilated, 

 simple posteriorly. 



Shell sub-spiral, ear-like, thin, hyaline, covered anteriorly 

 by a fold of the mantle, deeply immersed, and partially con- 

 cealed posteriorly in a depression of the back, on the under 

 side showing the free columellar margin of all the whorls. 



Syn. Pectella, Gray. Gasotis, Shuttleworth. 



Ex. P. pallidum, Firussac, pi. 72, fig. G. Shell, P. 

 nigrolineata, Shuttleworth, fig. G, a. 



This genus comprises the Parmacella of the New World. 



