56 HELicnxsj. 



Var. II. Helmii. Like Var. I., but pearl white. 



5. Z. PURUS (clear). 



Compressed, extremely thin, dull, semi-transparent, light 

 brown horn-colour; very faintly striated in both directions, 

 and having consequently a reticulated appearance under a 

 microscope ; whorls four, the last very large ; mouth almost 

 circular ; umbilicus rather narrow, but deep ; diameter nearly 

 one-seventh of an inch. 



Found in many parts of Great Britain and Ireland, 

 but not everywhere. It is a very fragile shell, and the 

 animal is difficult to extract entire. 



The variety is an exquisitely delicate object. 



The animal is cream-coloured. 



Var. margaritacea. Pearl white and nearly trans- 

 parent. 



6. Z. EADIATULUS (slightly rayed). 



In size and shape resembling the last species, but highly 

 glossy ; darker in colour, and exquisitely marked by 

 regular curved striae in the line of growth more strongly 

 above than below ; whorls four and a half ; diameter nearly 

 one- seventh of an inch. 



Dr. Jeffreys says that this species frequents moister 

 places than Z. purus. It is not abundant though widely 

 distributed in Great Britain and Ireland. Under a 

 lens it is a beautiful object, and when once seen need 

 never be mistaken for the last species, but care should 



