72 Manganese in Land and Fresh Water Mollusca. 



Tree Trunk Scrapings 

 Beech, Aldenham, close 



green o-6 



1 ,, Hampden ,, 1-5 



1 ,, ,, grey lichens 8-2 



1 ,, ,, moss 15-8 



Oak, Aldenham, grey-grn. 0*4 



Mosses 

 From stone walls 

 old timber 



Large Fungi 

 (Agarics). 



2 Beechwood 0-7, 



Hedge bank 



Lepiota rhacodes 



Clitocybe sp. 



<o-o5 

 o-4 



0-2 

 0-2 



I'l, 



hedge bank 

 Water Plants. 



1-2 



1-3 

 i'3 



Potamogcton crispus 



P. nutans 



P. densns 



P. perfoliatus 



P. lucens 



P. pectinatus 



El odea (two loci) 



Lemna minor 



L. trisulca 



Nitella 

 Chara 



Moss 6 (floor of culvert) 690 

 ,, Fontinulis antipyretica 12 



1, 6 



14. 65 



4, 5 



7 

 28 



45 

 14. 23 



9 



72 



10 

 4 



Callitriche 

 Myriophyllum 

 Ceratophyllum 

 Ranunculus 

 Nymphcsa 

 Limnanthemum 

 Watercress 3 



16 

 19 



44 



77 

 26 



33 



8 



22 7 

 85 



Green slime (streams), 



20, 4 107, 377? 

 Brown slime (pond) 

 Deposit on stagnalis shells 8 41 

 Deposit on peregra shells 41 



These results show that whatever vegetation snails eat they 

 will get more or less manganese. The amount in water plants 

 is singularly larger — roughly about twenty times in the higher 

 plants — than in land species. It should, however, be noted 

 that the water plants were analysed as they were, being simply 

 washed under the tap and then dried. The figures include, 

 therefore, the manganese in any epiphytic life, which coats 

 most water plants, 9 and in any inorganic deposit 10 ; in the 



1 The trees from which excessively manganifcrons snails and slugs 

 were obtained (supra p. 18). 



2 The fungi on which the Avion ater with most managnese (supra 

 p. 18) was feeding. 



3 Sna ils were eating this freely ; stagnates g&vs 1*4 peregra, 4*4. 



4 L. peregra living among this gave 3*1. 



5 L. pert-grit living among this gave 3-6. 



c Eurhynchium vusciforme v. alopeciiroides. 



~> Ancylus fluviatilis living among this gave 21. 



S Deposit consisted largely of calcium carbonate. 



9 see e.g. J. ("r. Needham and J. T. Lloyd, Life oflnland Waters, ioi(>, 

 P- 336. 



10 A. Kerner and F. W. Oliver ( Natural History of Plants, 1002, Vol. I., 

 p. 261}, record 1*2 per cent, of manganese in the deposit on the leaves of 

 Potamogeton lucens. 



Naturalist, 



