40 PUOCEEDINGS OF THIO MALACOLOGICAL SOCIETY. 



Helicella caterata (Montagu). Helicella Heeipensis (Mabille). 



SIZE. 



Montagu gives the diunieter of JJs^uaWy hirger than IT. crqjeraf a. 



the sliell as " three-eightlis of an but not always so. Specimens 



inch, rarely half an inch ". This from the Thames Embankment 



equals 9-5-12-7 mm. The largest near Laleliam, Middlesex, do not 



examples which I possess from measure more than 8 to 9 mm. 



the south-east of England are, The average diameter is from 



liowever, all under 10 ram. in 10 to 12 mm. It sometimes, 



diameter. (In the west of Ire- however, exceeds 13mm. 

 land this shell attains a maximum 

 diameter of about 12 mm.) 



SPIRE. 



Spire usually distinctly raised, Spire low, and pyramidal 



and somewhat conical. rather than conical. 



SUTDRE. 



Marked hj a distinct furrow. Less distinctlj' marked. 



UMBILICUS. 



Well marked, deep, and of more Narrow, until the last "whorl 



or less uniform rate of increase is reached, then increasing with 



tlironghout. The reflection of the remarkable rapidity. The chief 



lip tends to obscure the umbilicus. superficial character of the shell. 



striation. 

 Very strongly marked, but At a rough glance the shell 



irregular and rugged when appeals to be smooth. In i-eality 

 examined closely. it is closely, finely, and regularly 



striated in comparison witli 

 If. caperata. 



PERISTOME. 



Sharp, and not reflected, except Sharp, but more delicate than 



towards the umbilicus. Furnished that of H. caperata. The in- 

 with a strong white internal rib. ternal rib is frequently of a flesh 



colour, and is not so strongly 



marked. 



habitat. 

 More commonly met with in Hedges and grassy banks. 



open and uncultivated ground Common in the autumn months 

 than in shady places. in certain places on the withered 



stems of Sisymh'ium officinale. 

 upon -which its colouring renders 

 it great protection. 



The range of this shell would appear to be confined in these islands 

 to southern Britain. Thanks to Mr. A. G. Stubbs — who appears to 

 have been the first in this country to observe the differences between 

 these two shells, but has not published his discovery — and Mr. A. S. 

 Kennard, I am able to record it liere from manv localities that I have 



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