244 SNAILS AND SLUGS [CH. VII 



(6) Teeth 4 or 5. 



moulinsiana (Dupuy), y 1 - ', shell with rib, umbilicus open. 



A restricted species ; has been found at Wicken Fen, 



Cambs. (H. H. B.) 



pygmcea (Drap.), yY', rib very stout, umbilicus narrow. 

 alpestris (Alder), y^", shell not ribbed, suture very 



deep. 

 (c) Teeth 6. 



substriata (Jeff.), yV', aperture semi-oval ; tumida yY', 



aperture heart-shaped. 

 antivertigo (Drap.), yY', aperture triangular. 



Family 

 genus Balea (Prideaux) Gray, shell sinistral, aperture ovate. Bark 



of trees and mossy walls. 

 perversa (L.), " ; top whorl shining. 

 genus Clausilia Drap., shell sinistral, aperture with clausilium. 



Bark of trees and under stones. 



(1) margin of clausilium notched. 



biplicata (Mont.), |", 2 folds on pillar, shell streaked. 

 laminata (Mont.), f ", 3 or 4 folds on pillar, shell smooth. 



(2) margin of clausilium entire. 



rolphii Leach, -|", 4 or 5 folds on pillar; shell fusiform 



and streaked. 

 Udentata (Strom.), ^", 3 folds on pillar. 



Family LIMACID^. Animal terrestrial ; shell internal, beneath 

 the mantle, rudimentary or shield-shaped ; tentacles four, 

 cylindrical, invaginable ; eyes at tip of dorsal pair. 

 genus Milax Gray, respiratory aperture in posterior half of shield, 



which is shagreened ; a well-marked dorsal keel along body. 

 g agates (Drap.), colour dark lead, sides pale. 

 sowerbyi (Fer.), colour tawny yellow, keel yellow. 

 genus Limax L., respiratory aperture in posterior half of shield, 



shield concentrically wrinkled. 

 flavus L., animal 4" ; yellowish with black -brown spots, but 



variable ; head and tentacles grey ; shell ^" long x " broad. 

 arborum Bouch-Chant, 3", grey with yellow spots, dark central 

 and lateral stripes ; shell nearly flat. 



