3/6 Shell Life 



the young arrive at full size in two years. I have 

 found the white variety in plenty living in caverns 

 wrought by other creatures in the rotten stump of 

 a felled beech, and fancy the deficiency of colour may 

 be due to the darkness of their habitat. The greenish- 

 white shell is certainly more protective amid such 

 surroundings than the ordinary colour would be ; and 

 it is not difficult to realise how natural selection would 

 brino^ about a distinct race of white Claiisilias under 

 such conditions. 



The Two-lipped Door-shell (0. h'qMcata) is slightly 

 less in size than C. lamiiiata, and instead of being 

 rounded and glossy the AAdiorls are com- 

 pressed and closely covered by fine but 

 distinct ridges, some of which are half 

 white. It is a duller, more grey-looking 

 shell than that of the glossy laininata, 

 but a further distinction is found in 

 the mouth. In laminata this is con- 

 tracted above into a narrow channel 

 like the lip of a jug; in hiplicata there is such a 

 lip below as well as above. It is a very rare species, 

 and has only been recorded from the counties of 

 AVilts, London, and Herts. The London localities 

 lie along the Thames between Putney and Hanuner- 

 smith, but recent municipal " improvements " have at 

 least restricted these. Fifteen or sixteen years ago 

 at Putney I could alwaj^s put my hand on a few 

 specimens for a conchological friend, but I under- 

 stand that an embankment of the most solid type has 

 improved away my particular hunting ground and 

 buried the Clausilias. Biplicata spends its days at the 

 roots of willow-trees, and at night ascends the trunks. 



