46 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



they develop early. Sometimes specimens are also found which 

 are intermediate in appearance between these two mutations. 

 This intermediate type, however, does not. seem to be the 

 result of a cross between individuals of the other two ; 

 experiments rather suggest that h is due to another dominant 

 hereditary factor which tends to reduce the effect of the 

 factor that retards the development of the bands, although 

 only producing a noticeable difference in about 70 per cent of 

 the shells. Further experiments, however, are needed for the 

 elucidation of these problems. 

 3, "A note upon certain Fossils of the Upper Tertiary beds of 



the Dardanelles." By Paul Pallary. 



Dr. Bowell exhibited photographs from micro-slides of the radulae 



of Polita cellaria, Miill., and Limncea palustris, MiilL, originally 



mounted in the year 1852 and remounted this year — 1920. 



Dr. Boycott exhibited a series of maps used by Mr. Eoebuck in 



preparing the Census of Distribution of British MoUusca. 



ORDINARY MEETING. 

 Friday, 9th April, 1920. 



J. R. LE B. TOMLIN, M.A., F.E.S., Vice-President, in the Chair. 



Mr. Gr. C. Spence was elected to membership of the Society. 



The following communications were read : — 



1. " Further notes on Radulae." By Dr. E. W. Bowell, M.A. 

 In the Testacellidse all our three species can be easily 

 and definitely discriminated by means of the radula. The 

 central tooth is smallest in T. haliotidea, Drap. 



In the genus Limax (sensu lato) we have adult forms 

 {maximus, cinereo-niger, and flavus), a peculiar form {L.arhorum), 

 and nepionic forms {L. tenellus, Agriolimax agrestis, and 

 A. Icevis). The points of distinction and relationship of these 

 were described in more detail. 



The two Milaces are very similar, but apparently separable. 

 (Only thirteen specimens of Milax gagates had been examined, 

 however, this total including no very large specimens.) 



The reintroduction of the generic name Zonites was urged ; 

 it is noted that Z. algirus is an adult form, while our larger 

 species are nepionic ; nitidulus, however, is of the algirus 

 type. The striking smallness of the central uncus in lucidus, 

 cellarius, rogersi, and alliarius is explained by the folding of 

 the radula and the increase in size of the pleural unci. It 

 does not appear to be a character calling for the formation 

 of a separate genus. Z. scharffi is considered as probably 

 typical cellarius, Z. hibernicus as a local race of cellarius. 

 The previously described distinctions are well maintained, 

 but are considered to be of less than specific importance. 



