rARlWRHlHI' : HKl.lX NEMOKAI.IS AND HKI.IX HORTENSIS. 317 



In this colony //. hortensis is more numerous than the latter 

 species ; as in the other cases considered FI. arbiistorum is plentiful, 

 being quite as numerous as H. Jiortensis. 



Cavedale, Castleton. 



On the Castle (north) side of Cavedale a small colony o{ H. hortensis 

 and H. nemoralis is found. The hillside is covered with moderately 

 long grass ; the limestone frequently crops out and gives to some 

 areas a stepped appearance. Along the top nettle clumps are found, 

 but the area in question has little or no variety of plant life. 

 B. nemoralis is found over the whole of the habitat and is represented 

 by the varieties libellula and rubella^ but although odd shells of 

 H. hortetisis are found throughout the area it is in the neighbourhood 

 of the nettle clumps that this species is most numerous ; it would 

 appear, therefore, that the two species are not truly associated in this 

 colony. Once again we find H. arbustorum present and here it 

 seems to confine itself almost entirely to the nettle clumps. 



The Win NATS, Castleton. 

 On both sides of the Winnats a considerable number of -fi^. nemoralis 

 is found. This habitat is a wind swept gorge, the sides of which are 

 scarred with limestone cliffs. The sides are covered with a short 

 variety of grass and there appears to be little or no other vegetation 

 present, with the exception of one or two small nettle clumps which 

 are found on the upper reaches of the hillsides. In this colony the 

 following varieties are found : — libellula ooooo, libellula 00300, 

 libellula ooooo albolabiata, casfanea ooooo, castanea 00300, castaiiea 

 ooooo albolabiata, rubella ooooo and rubella ooooo albolabiata. 

 H. hortensis is not found in this habitat, but H. arbustorum is found 

 along the bottom of the hillside, while H. lapicida is to be found on 

 the outcropping limestone. 



Summary and Conclusion. 

 In the case of H. hortensis no appreciable fluctuation in the size 

 was noted from colony to colony and in all cases only band varieties 

 of the type were found. H. nemoralis, however, varies considerably 

 in size and banding and several interesting comparisons can be made. 

 The shells from the colonies at Cavedale and Millers Dale are 

 similar in size and marking, the bands being broad and deep in 

 colour, but while only the third 'band is present on the Millers Dale 

 shells the tendency at Cavedale is for the full complement to be 

 present. Also the shells from Deepdale and the Winnats agree very 

 closely in colour, size and banding; an exception, however, must be 

 made in the case of the variety libellula ooooo albolabiata which is as 

 small as a small H. hortensis in the '\^'innats, while in Deepdale 



