Geographical Distrihiition of Mollusca. 



381 



ordinarily fibrous epidermis. In this connection the habitat 

 of H. obvoluta in the south is of interest, for being of the same 

 nature, it is confined also to Beech woods. 



Acanthiniila lamellata Jeff. Associated species : — 



Vitrina pellncida Miill. 

 Vitrea alliaria Miller 



,, pur a Aid. 

 Euconulus fulvus Miill. 



Acaiithiniila aciileata Miill. 

 Carychiwn minimum Miill. 

 Acicula lineata Drap. 



A. lamellata, a Northern type, is extremely local, but 

 dominant over A. aculeata, where it does occur. A. aciileata 

 belongs really to the Oak-Birch section of the northern district, 

 but is well distributed throughout. The association of A. 

 lineata is not always maintained. The association is charac- 

 teristic of the leaf carpet which, lying in damp soil in the woods, 

 is thickly permeated with fungoid growth. 



Hygromia hispida L. Associated species : — 



Vitrina pellucida Miill. 

 Vitrea cellaria Miill. 



nitidiila Drap. 



pura Aid. 



Cochlicopa htbrica Miill. 

 Carychiitm minimum Miill. 

 Hygromia riifescens Penn. 



This species, which is usually of a smaller and more hispid 

 form than the true type, is universally distributed, but occurs 

 in marked abundance among dead beech leaves, especially 

 towards the margin of the woods. We have taken it thus in 

 great abundance, and of a large size in similar habitats in the 

 Midlands, which would seem to strengthen the evidence as to 

 its preference for the Beech. The distribution of this species 

 in the Ash wood^ of the Carboniferous Limestone is maintained 

 to an altitude of about 400 feet, thus forming a connecting 

 link with the higher and drier woods, the association becoming 

 restricted to V. nitidula and V. pura. 



{b) — Dry Section : Shallow soils of the upper woods. 

 Clausilia bidentata cravenensis Taylor. Associated species : 



Pyramidula rupestris Drap. 

 Pupa cylindracea da Costa. 

 Clausilia bidentata Strom. 



Clausilia laminata Mont (rare). 

 Ena obscura Miill. 



This well-known characteristic Craven shell is found in 

 abundance on the limestone scars sheltering the lower wood. 

 It is not a ground species like C. laminata, and is rarely taken 

 on the trees. Unlike C. bidentata, it is entirely confined to the 

 Carboniferous Limestone. 

 1909 Nov. I. continued). 



