Boycott : Manganese in Land and Freshwater Mollnsca. 211 



■other large bivalves, which affect quite different habitats, in 

 having a high manganese content, and indeed on the average 

 considerably exceeds Unio and Anodonta. Specimens from the 

 Wye at Hereford gave 152 and 131, from Glengariff, in Cork, 

 151 and 212, from the Taw, in Devon, 103, and from the Irt, 

 in Cumberland 38, mean 116. Limnaea peregra from the Taw 

 had 9 (average 4), and the slime of algae on the stones had 

 accumulated even more than the mussels, giving 369. But 

 manganiferous surroundings by no means result in a snail 

 having much : thus the bodies of Dreissena polymorpha from 

 the canal at Agbrigg gave 2 and their black encrusted byssus 

 as much as 610 ; a similar comparison on specimens from 

 Wakefield showed 4 and 342. 



Analyses of plants are too few for more than brief notice. 

 "Water plants (max. yy in Ranunculus aquatilis) , algae 

 (max. 369), liverworts {Riccia fliiitans 236), and mosses 

 (max. 890 in Eurhynchium ritsciforme) have on the whole 

 much more than land plants. Among the latter the leaves 

 of trees and mosses have most (beech up to 26, Thuidium 

 tamariscinmn 10), herbs, fungi, and lichens very little 

 (generally i or less), liverworts rather more. They doubtless 

 vary widely with the locality. 



The shells of the moUusca have not been examined in 

 'detail. Those of Bulimimis montanus, Zonitoides excavatus 

 and Unio pictorum show only traces. The encrusting deposit 

 on Limnaea and other water shells may contain considerable 

 quantities. 



The Tunbridge Wells Literary Society has issued a four-page pamphlet 

 -which contains an account of the annual meeting, and of the Rev. T. R. R. 

 Stebbing's Presidential Address. 



The Bristol Museum and Art Gallery has issued its report for the year 

 •ending September, 1920, this being the hundredth year of the Institution's 

 existence. We should like to congratulate our Bristol friends on their 

 excellent work during a century. 



Among the contents of the Belfast Natural History and Philosophical 

 ■Society's 'Report recently received, we notice " North of Ireland during 

 the Glacial Period,' by Dr. Dwerryhouse, and several papers of more 

 general interest, which do not, however, bear much upon the district. 



The Proceedings of the Croydon Naturalist History and Scientific 

 Society contain the Presidential Address of Mr. A. F. Major on ' Surrey, 

 London, and the Saxon Conquest, ' as well as ' The Home Life of Badgers,' 

 by Miss L. E. Cheesman, and ' Report of the Meteorological Committee, 

 1919,' prepared by Mr. F. Campbell-Bayard. The last item is a remark- 

 ably complete record. 



The four parts of the Journal of the Northants Natural History Society 

 and Field Club, for 1920, have recently been received. Among the con- 

 tents are a series of well-illustrated papers on ' The River System of 

 Northamptonshire,' by B. Thompson ; ' A New Northamptonshire 

 Member of the Characeae,' by H. N. Dixon ; ' Rosa Litigiosa in North- 

 ants,' by G. C. Bruce, and various shorter notes and observations dealing 

 ■with Hislory, Conchology, Botany, Meteorology, etc. 



1921 June 1 



