50 HYALINIA HELVETICA. 
partial to living amid moist, dead leaves and amongst thick, damp moss, 
being often very plentiful under such conditions, even in larch woods. 
Under certain circumstances it gives off a more or less pungent odour of 
garlic, though this faculty is not so pronounced or invariable as in //yalinia 
aliaria. It is very indifferent to cold and in ordinary seasons scarcely 
hibernates at all. ‘The heart of a specimen examined about mid-day in 
June was found to pulsate about the rate of sixty times per minute at a 
temperature of 62° Fahr. Though probably chiefly vegetarian in habit, 
it is also very predatory, and in captivity has been known to kill and 
devour examples of Melia hispida, Patula rotundata, Hyalinia Salea, 
and Vitrina pellucida, confined in the same receptacle. 
Reproduction and Development.—No details are known nor have 
observations been recorded of the congress of this species. ‘I'he seminal 
element is, however, known to be transferred by means 
of a spermatophore and pairing has been observed at fw 
Marple as taking place in April, by Mr. W. Moss, and 
by Mr. Lionel I. Adams at Merstham in Surrey in Fic. 85.—Spermatophore 
October, while Mr. Hainsworth found amongst others 9), 4,,21a7Ple x. 6 (after a 
normally employed, an adult specimen paired with an photo. by Mr. W. Moss), 
adolescent Helix rufescens at Addingham, Yorkshire, in August 1906. 
Geological History.-—-I"or this species only one locality is as yet 
known, the Pleistocene deposit within the Ightham fissure near Wrotham, 
West Kent, where several specimens have been found. 
Variation.—The variation in the external morphology of the present 
species would appear to be not very great, the published records only 
showing that the albino form and one in which the whitish basal opacity 
is more sharply delimited have as yet been registered. 
The internal organization is, however, much more unstable, the denticles 
of the odontophore being exceptionally irregular numerically and morpho- 
logically, and the re productive organs being also described by Mr. Moss as 
varying very greatly in their form and in the relative proportions and 
development of the different parts. 
The large, darkly coloured and more widely-umbilicate shells discovered 
by Mr. J. W. Jackson in Yorkshire, and here described as var. wmbilicata, 
but of which the internal structure is unfortunately as yet quite unknown, 
have externally their closest affinity with the specimens found in Highgate 
Woods and at Finchley in Middlesex by Mr. J. i. Cooper, and by “Mr. 
©. Oldham at Bettws-y-Coed in Carnarvonshire. 
The specimens from these localities, while resembling the widely- 
umbilicate forms externally, correspond most closely as reg ards the radula 
with the more narrowly perforate typical form iamed Vitren rogersi. by 
Mr. B. B. Woodward, which he described as possessing an odontophore 
one-third larger than that of Myalinia alliaria, and as bearing about 
forty transverse rows of denticles. 
The Middlesex and Carnarvon specimens, as compared with the more 
narrowly perforate typical form from Anglesey and elsewhere, are said to 
show a slightly larger radula, and somewhat more numerous transverse 
and longitudinal rows of teeth thereon, features, however, which may be 
due to the relative age of the individuals examined and to differences 
possibly arising during the process of preparing the radula. 
According to the careful observations of Messrs. Moss and Boye ott, the 
more openly umbilicated Middlesex and Carnarvon specimens examine 1d by 
