41 6 MILNE : CONTRIBUTIONS TOWARDS IRISH MOLLUSCA. 



Z. radiatulus, however, though a common Irish species, I 

 had not expected ; its occurrence in the fields at the 

 Colony may be a relic of old times, as the cultivation of 

 the land there seems of long standing — Dugort, close by, 

 getting its name of the meadow village therefrom — and 

 it is found in the deposits ; so that it may have retreated 

 before the peat, which supplanted the forests, into this 

 httle patch of cultivated ground. The same process may 

 have applied to 



Z. crystallinus which also occurs in the fields at the Colony, 

 as well as in the deposits ; also on Innishbiggle ; and to 



Z. fulvus which, however, has not the same proof of its 

 antiquity, as it is not found in the deposits, but lives at the 

 Colony; the form is a small one referable to var. Alderi. 

 These three species were all plentiful in their locality ; 

 another, which might seem to be dying out, is 



Z. nitidus, of which only one specimen was to be found on 

 the warren, and which above all would appear to be a 

 survival of forest times. 



To proceed to the Helices. 



Helix aspersa occurred in great plenty on a confined space, 

 on the shell-mounds at Keel ; the shells were all rather 

 dark, ranking under the vars. flammea, undulata, and 

 obscurata. Now this species was not found in the 

 deposits — either on the warren or in the shell-mounds — on 

 the top of which it was living ; and as by reason of its size 

 it could hardly have been missed had it been there : from 

 this and from its occurrence in such numbers over a small 

 area, I judge that it is a recent introduction which has not 

 had time to spread. It is found in spots here and there 

 on the mainland near, and similarly throughout Ireland, so 

 far as my observation goes, it is, though generally dis- 

 tributed, only numerous within confined boundaries, so 

 that possibly the spreading process is going on throughout 

 the island. On the other hand, 



J.C, vi., Oct., 1891 



