314 JOURNAL OF CONCHOLOGY, VOL. l6, NO. lO, OCTOBER, I922. 



truly associated in this area ; although H. hortensis occurs over the 

 whole area from the Tideswell road to within a few yards of the lower 

 road, it is only very occasionally that H. tiemoralis is found with it. 

 Over the remaining few yards the reverse is true : in this small band 

 H. nemoralis is found in large numbers, while the smaller species is 

 of much less frequent occurrence. 



Before passing on to a consideration of the second colony it may 

 be of interest to note the frequency with which the several varieties 

 of the two species occur. In the case of H. hortensis the ground 

 colour varies from a pale to a rich yellow and out of one thousand 

 (1,000) specimens two hundred and eighty-five (285) were devoid of 

 banding, while the remaining seven hundred and fifteen (715) had 

 almost without exception the normal complement of bands. In the 

 case of the banded forms, there is a noticeable tendency towards a 

 thinning out and ultimate disappearance of the second band. Among 

 the pentat^niate shells, coalescence of the various bands frequently 

 occurs; band varieties which have been noted include the following : — 

 123(45). i(23)(45)> 02345, (12)3(45), (r23)(45), (12345), (12)345- 

 Of the H. nemoralis by far the majority were found to belong to the 

 variety libellula 00300, and of one thousand (1,000) specimens nine 

 hundred and nine (909) were of this form ; of the remainder thirty- 

 seven (37) were rubella 00300 and fifty-four (54) belonged to the 

 variety libellula 00000. In addition to these varieties two shells of 

 the variety rubella 00000 and one each of libellula 12345 and libellula 

 123(45) were found. 



The difference between the habitat of this colony and that above 

 the Tideswell road is very striking : in the latter case we have a grassy 

 bank broken here and there hy miniature limestone cliffs, on which is 

 found a much more varied flora than is met with below the road. 

 Here in addition to grass and nettles are found vetches, several 

 species of moss together with some of the commoner roadside plants. 

 In this colony we can say that the two species are truly associated 

 for they are found side by side throughout the whole colony ; although 

 H. hortensis is more frequent it cannot be said that the percentage of 

 one species is higher in one part of this colony than in another. As 

 in the neighbouring colony only two varieties of H. hortensis and 

 three of H. nemoralis are found, but in the case of H. netnoralis the 

 variety rubella 00300 is much more numerous. 



In both stations H. arbustorum abounds ; in the first area it is 

 confined almost entirely to the nettle beds which cover tlie mounds 

 of mud, but in the second colony it is found associated with H. 

 nemoralis and H. hortensis throughout the whole of the habitat. 



