HELICIDiE. 121 



airvalve, when closed, with a black spot, when open, 

 surrounded by a black ring. (Sturm, Fauna, t. 9. ; 

 Pfeiffer, 1. c.) 



Shell half an inch in diameter, not so much in height, 

 extremely thin and transparent, of a pale watery green, 

 and quite smooth ; volutions three, the first very large 

 and a little oblique, the others but little raised and 

 ending obtusely; aperture very large, oval-elliptic, 

 rather oblique, interrupted at top by the prominency 

 of the second volution, with the margin thin and 

 membranaceous, often coloured with a pale brown 

 border, without internal rib ; the suture well marked, 

 and when magnified, exhibiting a striated spiral line ; 

 pillar lip a little reflected, and forming a slight con- 

 cavity, but not an umbilicus. 



1. Shell varies as to the colour of its suture; in 

 some this is whitish and more wrinkled than ih others ; 

 in some it is brown ; whilst in others, the brown, in 

 particular lights, appears as if gilded. 



2. The green colour of the shell also varies in 

 hue. 



Mr. Jeffreys has described three British species of 

 the genus, but Mr. Alder observes, that " Mr. Jeffreys 

 having kindly favoured me with specimens of his V. 

 Draparnaudi, I compared them carefully with speci- 

 mens of Helicolimax Audebardii Fer., collected on the 

 Continent, and have come to the conclusion that they 

 are not of that species. I am afraid that V. Draparnaudi 

 can only be classed as a variety of V. pellucida (Helico- 

 limax pellucidus Fer.). Mr. Jeffreys now considers his 

 V, diaphana to be only a variety of the same. V. 

 Dillwynii appears to be something different ; but being 



G 



