Quarterly Journal of Conchology. 139 



I was then surprised to find scarcely any difference between the 

 island and mainland species. Generally the Soil Ionian shells are 

 somewhat thinner and more fragile than those on the mainland, 

 probably because the islands (being composed wholly of granite) 

 may be wanting in lime. H. Aspersa was smaller than our usual 

 shells and Limruza Peregra was of the small variety " Maritima " 

 found near the sea-coast. H. Sericea was plentiful and larger than 

 specimens which I have from the mainland. But the other shells 

 did not differ (so far as I saw) from the corresponding mainland 

 specimens. It still appears singular to me that such a peculiar 

 situation, with so little chance of crossing with individuals modifi- 

 ed by different conditions, should have had almost no visible effect 

 on the Scillonian land-mollusks. But on the other hand it must 

 not be forgotten that our British land-shells seem to be generally 

 of species which can bear great variations of climate, &c, or we 

 should not find our living individuals so little altered from the semi- 

 fossilized specimens which are found in the Brick-earth. The Cave- 

 Lion, Mammoth, Rhinoceros, Reindeer, &c, living in the 

 British Islands when the Brick-earth was deposited, have all 

 died out ; but the changes which proved fatal to their continuance 

 have scarcely modified the land shells. The tenacity of form I had 

 clearly undervalued when I expected to find in the Scillonian 

 specimens of our British land-shells marked effects of their isolated 

 situation. 



A White variety of Limnaea palustris taken at South- 

 port. — Whilst collecting shells at Southport on July 25th. 1876. 

 I found a good quantity of Physa hypnorum and Limncea palustris 

 and amongst the latter I was so fortunate as to take a pure white 

 variety, though all the others (of which I got some dozens) were 

 of the usual color. This mustbe very rare, as I have never seen 

 it before, and the only mention lean find of it is in No. 2 of the QJ.C 

 — Edward Collier. 



