ALKINS: TWO MOLLUSCAN ASSOCIA'lIONS IN NORTH-EAST STAFFS. 295 



be found al)undantly, in association with H. arbustonim but not with 

 H. nemoralis. The forms ooooo, 12345, (12345), (123X45), 1(23)45 

 (^2)3(45) have been taken here. 



6. Alton. 



(a). Near Dr. Hall's surgery H. hortensis has occurred; the 

 writer has no record of the forms, and has not seen any H. neinoralis. 



(b). Amongst nettles and brambles by a garden just below the 

 Roundhouse; a large colony of H. hortensis with very few H. 

 ntmoralis (perhaps one to fifty). Of H. hortensis the band varieties 

 ooooo, 12345, i(23)(45), 1(23)45, 1(2345), (12345), and of H. 

 fiemoralis the var. rubella 12345, 00300 have been recorded. 



7. Along the hedgerows near Gallows Green H. nemoralis occurs 

 very sparingly; vars. rubella 003 3 00; rubeUa-fascialba 00300. No H. 

 hortensis. 



8. Finally, ow the roadside, Quixhill, Denstone, both species 

 occur together, though not in any great abundance ; H. hortensis is 

 about twice as common as H. neiiioralis. Of the former the writer 

 has the vars. 12345, (12345), 123(45), ooooo, and of the latter the 

 vars. libellula ooooo; rubella ooooo, 00300. The H. nemoralis are 

 particularly fine. 



Thus there are at present known to the writer in non-limestone 

 districts eight stations for H. nemoralis alone, three for H. horte?isis 



alone, and only three where the two species occur in association 



and in the case of two of these three H. nemoralis is greatly out- 

 numbered by H. hortensis. The contrast with conditions on the 

 limestone is thus very marked. 



It is very probable that the stations enumerated in the above list 

 will be added to in the future. The writer hopes to be able to con- 

 tinue his observations in this and other districts, and has only 

 ventured to present this note in the hope of creating or stimulating 

 interest in this and kindred problems more particularly, perhaps, 

 among the younger members who have recently joined the Society in 

 the Manchester neighbourhood, without desiring to hazard generalisa- 

 tion from too Sjcanty data. Yet the facts above cited do seem to 

 afford support, so far as they go, for the suggestion already advanced, 

 that the two species we have been considering appear to have 

 established themselves first in the limestone districts, spreading thence 

 at a later date in a more or less sporadic fashion over the neighbour- 

 ing areas, where they have become modified in the course of time in 

 the direction of some general increase in size and of the development 

 of bands {H. nemoralis), or of increasing the width of bands already 

 present (ZT. horteftsis). 



