II SELF-BURIAL OF SNAILS 4 1 



themselves to grow ; H. rotundata burrows into decayed wood ; 

 Hyalinia radiatula appears to remain on decaying blades of 

 grass ; Pupa umhilicata^ Clausilia rugosa^ and Buliminus obscurus 

 bury their heads only. 



The observations of Mr. W. E. Collinge^ do not at all agree 

 with those of Mr. Lowe, with regard to the mode in Avhich land 

 Mollusca enlarge their shells. He bred and reared most of the 

 commoner forms of Helix and also Clausilia rugosa^ but never 

 saw them bury any part of their shell when enlarging it. While 

 admitting that they may increase their shells when in holes or 

 burrows of earthworms, he thinks that the process of burying 

 would seriously interfere with the action of the mantle during 

 deposition, and in many cases damage the membranaceous film 

 before the calcareous portion was deposited. Mr. Collinge 

 has found the following species under the surface in winter: 

 Avion ater (3-4 in.), Agriolimax agrestis (6-8 in.), Hyalinia 

 cellaria and H. alliaria (6-8 in.), Hyalinia glabra (5 in.). Helix 

 aspersa (b-Q in,), H. rufescens (4-6 in.^^ H. rotundata (4-5 in.), 

 H. hispida (7 in.), Bidiminus obscurus (4-6 in.), B. mo7itanus^ 

 (24 in.), and the following in summer, Hyalinia cellaria and 

 alliaria (6-8 in.). Helix rotundata (4-5 in.), Balea perversa 

 (6-8 in.), Cyclostoma elegans (3-4 in.). The same author has 

 found the following species of fresh-water Mollusca living in 

 hard dry mud : Spliaerium corneum (3-14 in.), *S'. rivicola (p-Q 

 in.), S. lacustre (10-14 in.), all the British species of Pisidium 

 (4-12 in.), Limnaea truncatula (18 in., a single specimen). All 

 our species of Unio^ Anodonta^ Bithynia^ and Paludina bury 

 themselves habitually in fine or thick wet mud, to a depth of 

 from 4 to 14 inches. 



This burying propensity on the part of Mollusca has been 

 known to play its part in detecting fraud. When my friend 

 Mr. E. L. Layard was administering justice in Ceylon, a native 

 landowner on a small scale complained to him of the conduct of 

 his neighbour, who had, during his absence from home, diverted 

 a small watercourse, which ran between their holdings, in such 

 a way as to filch a certain portion of the land. The offender 

 had filled up and obliterated the ancient course of the stream, 

 and protested that it had never run but in its present bed. 



1 Naturalist, 1891, p. 75 f. ; Conchologist, ii. 1892, p. 29. 



2 Taylor, Journ. of Conch. 1888, p. 299. 



