1 8 Manganese in Land and Fresh Water Mollusca. 



have been noted which suggest that locality has a good deal of 

 influence, and locality is, in this connection, most easily in- 

 terpreted as food. Thus, M. sowerbyi and A. hortensis collected 

 together in one garden gave 13 and 12 ; from another garden 

 only 3 and 6. The mean figure for H. cell aria from Aldenham 

 district is 15 ; one locality gave as little as 3, and the nitidula 

 which accompanied it 2, compared with a local mean of 10 ; 

 another locality 4, and the helvetica with it 6, instead of 17. 

 Both these localities were in wet places by the river side, and 

 cellaria from a third similar place gave only 7, the figures for 

 drier loci ranging from 17 to 34. It is difficult to resist the 

 conclusion that in this particular sort of place Hyalinia has a 

 specially low content in manganese and the suggestion that 

 this is due to a difference in food. A third example is afforded 

 by a series of mollusca collected one day in the great beech 

 woods near Great Hampden, in south Buckinghamshire. x 

 The mean figure for Limax maximus from other localities is 9, 

 from here 56 ; the mean for A. ater 2, 2 from here 47 ; for 

 Hy. alliaria 39, from here 99. L. arborum (270), A. subfuscus 

 (274) and L. cinereoniger (86), gave very high figurres, though 

 there are no others for comparison ; the highly manganiferous 

 B. montanus and obsairus also occurred here. Altogether, 

 therefore, the locality is evidently one which encourges a high 

 content in manganese, and since all the species except ater 

 were taken crawling on beech trunks, one may suppose that 

 this habit has something to do with it. 3 On the other hand, 

 all snails from the beech woods do not show exceptionally high 

 figures, e.g., rujescens, 4 " lapicida and laminata, and in apparently 

 similar woods on the Cotswolds (where the Bulimini give the 

 same high figure) rufescens, lapicida, nemoralis, and even 

 alliaria. 5 The chief locality in Aldenham for caper ata is a beech 

 wood with bare floor, where the species occurs freely, climbing 

 up the trunks, but it has no more than the normal manganese 

 content, though A. agrestis from die same wood has twice the 

 normal amount. 



(To be continued), 



1 A delectable locality indicated by Mr. Charles Oldham (Journ. I 



Vol. XIII. (191 1 ), p. 148) ; the woods are supposed to be some of the Jew 

 remnants of the ancient forest of Bernwood (A. H. Allcroft, Earthwork of 

 England, 1908, p. 29a). 



2 A specimen from the roadside chalky bank close to the woods gave 

 only 1 . 



3 In W. A. Gain's experiment, lichens, moss and the green growth on 

 b^ech were by no means favourite foods. 



4 vufescens alone does not commonly climb up the trees. 



5 The habit of Alliaria to walk about openly in the daytime on tires, 

 walls, etc., is relatively unique among the Hyalinia, and is presumably 

 associated with its nasty taste (Lancashire Naturalist, Vol. VII. (1914), 

 P- 3")- ; 



Naturalist, 



