ZOOLOGY 



MOLLUSCS 



The physical structure of the county of Leicester ought to be favourable 

 to molluscan development, being well diversified ; and if the portion to the 

 west of the Soar, where the Trias comes to the surface, affords less favourable 

 soil than the secondary rocks to the east of that river, the Great Chalky 

 Boulder Clay, which covers much of the central as well as the eastern por- 

 tions of the county, should largely equalize matters for the land snails. 

 The water drainage, on the other hand, is so extensive and varied that 

 many suitable habitats are afforded for the water snails. 



Nevertheless the county has been rather neglected by malacologists in 

 fact only two papers of any note have appeared on its molluscan fauna: 

 one by J. Plant, compiled in 1850, but only brought to light and published 

 in 1887;* and the other by H. E. Quilter detailing the specimens found by 

 him between 1885 and 1887,* which practically formed the basis of the 

 list in the Records of the Conchological Society. This last, however, did 

 not include results from what might be expected to prove the most pro- 

 ductive districts. We are further indebted to Mr. A. R. Horwood of the 

 Leicester Museum for notes principally of additional localities. 



Altogether 92 species out of the 146 or so recorded for the British 

 Islands, have been met with in Leicestershire, and this is a very fair average. 

 The number will probably be further increased when more extended re- 

 searches shall have been made, especially in the limestone districts. 



Two, or three, more species of slugs, several of the small Vertigos, 

 as well as some other species ought certainly to be found in the district. 



Plant's record of Zonites lucidus has had to be rejected on account of 

 the uncertainty attaching to the identification of the species so designated. 

 It certainly had nothing to do with the Vitrea lucida now recognized as 

 British. The records of Clausilia laminata prove so far to be errors for 

 C. bidentata and have been omitted. 



An attempt was made without success to introduce the Roman snail 

 (Helix pomatia) into the county, in 1845, when a number of specimens 

 was turned out near Leicester ; but no survivors have been recorded though 

 dead shells have been gathered. 



Owing to Leicestershire's central position none of the more typical 

 northern, western, or southern species are present. 



The nomenclature adopted in the following list is that of the Con- 

 chological Society issued in 1904, and differs from that employed in the 

 earlier county histories of this series. Where the names here used differ from 

 those previously given, the latter are added in square brackets in order to 

 facilitate comparison. 



1 Tram. Leic. Lit. and Phil. Soc. i, pt. 2, pp. 22-33. ' Op. cit. i, pt. 7, pp. 17-21 ; pt. n, p. 36. 



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