12 Manganese in Land and Fresh Water Molhisca. 



The results are expressed below as parts of manganese per ten 

 thousand parts of dried snail body. Owing to the small amount 

 of material available, 1 accurate measures in the case of species 

 poor in manganese have not always been achieved, and with 

 the smaller species ' trace ' signifies something less, and gener- 

 ally much less, than i part. At present, however, all I seek 

 to show is that some species have very much less than others, 

 leaving the precise amount for future enquiry. 



In the following systematic catalogue of the results I have 

 noted the localities and some data as to habitats which may 

 be germane. Many are local specimens from the neighbourhood 

 of Aldenham in South Hertfordshire. 



Gastropoda pulmonata. 

 Testacella maugii. Hereford (garden) 1-5. 

 Limax maximus. v. concolor, Aldenham (garden) young 5, 23 

 adult 6, 12 ; Hampden, Bucks (beech wood) 56 ; v. fasciata 

 St. Albans (garden) 9 ; Aldenham (hedge-bank) 2. Mean 16. 

 L. cinereoniger. Hampden (beech wood) 86. 

 L. flavus. St. Albans (garden, hole in lime tree) 1-3. 

 L. arborum. Hampden (beech wood) 270. 

 Agriolimax agrestis. Aldenham, five loci (fields and hedge- 

 banks) 5, 6, 6, 6, 8 ; beechwood 13; St. Albans (garden) 

 14 ; Holmer, Hereford (garden) 2. Mean 9. 

 Milaxsowerbyi. All from gardens ; Aldenham 3, 8 ; St. Albans 



2 ; Hereford 13 ; Holmer 3. Mean 7. 

 Vitrina pellucida. Aldenham, three loci, less than 2. 1, 3. 



Mean 2. 

 Hyalinia lucida. Portmadoc, Carnarvon (1913) 23 ; (1914) 



7. Mean 15. 

 H. cellaria. Ludlow, Shropshire 16 ; Castleton, Derby 25 ; 

 Tremadoc, Carnarvon 71 ; Compstall, Cheshire 23 ; 

 Symond's Yat, Gloucester 25 ; Barton, Lancashire 7 ; 

 Aldenham, six loci 3, 4, 7, 17, 24, 34 ; Long Lane, Middle- 

 sex 27. Mean 22. 

 H . helvetica. Bicknor, Gloucester (1913) 14 ; ditto (1915) 35 ; 

 Marple, Cheshire 69 ; Tremadoc 49 ; Aldenham, seven 

 loci, 6, 10, 13, 16, 2^, 24, 26. Mean 26. 

 H . alliaria. (a) from trees in beech woods, Hampden, Bucks. 

 99 ; Cranham, Gloucester 6 ; (b) woodlands, Credenhill, 

 Hereford 62 ; Miller's Dale, Derby 3 ; Romiley, Cheshire 

 71 ; Aldenham n ; (c) mossy stone wall, Portmadoc, Car- 

 narvon 43 ; (d) ruins under stones, Ludlow 1.4 Mean 39. 

 H . nitidnla. Marple 85 ; Tremadoc 73 ; Ludlow 22 ; Castle- 

 ton 17 ; Chepstow, Monmouth 6 ; Barton, Lancashire 8 ; 

 Aldenham, three loci 2, 9, 20. Mean, 27. 



1 Many species are inconveniently small : about So dried bodies of 

 Hy. nitidnla go to a gramme, about 30 H. rufescens and some 400 A ncylus 

 fluviatilis. 



Naturalist, 



