JACKSON: ATTEMPT TO BREED FROM A SINISTRAL HELIX POMATIA. 345 



With reference to the growth of the shell in the case of the 

 sinistral specimen, I can only say that to all appearances this was put 

 on during the snail's active movements, as there was no indication of 

 its having buried itself for the purpose, although this appears to be 

 the rule (see A. H. Cooke, "Molluscs and Brachiopods, Cambridge 

 Nat. Hist.," p. 40). 



In concluding my observations I wish to tender my best thanks to 

 Mr. R. Standen for his kindly help and advice, and also for looking 

 after the snails on one occasion when I was absent from home. 



The Occurrence of the White Form of Helicigona lapicida (L.). — The 

 occasion of this special exhibit of white varieties of British land and freshwater 

 shells affords a good opportunity for enumerating some specimens of Helicigona 

 lapicida var. albina not hitherto recorded. In my collection I have a number of 

 this form, which were presented to me by Mr. R. D. Darbishire in igoi. These 

 he tells me were collected by him some fifty years ago on a rough wall in the 

 Zoological Gardens, Regents Park. From Mr. Darbishire I have also a white 

 specimen, labelled " Matlock," which he says he obtained many years ago on some 

 old Wt.lis on the hill-side to the northward of Monsal Dale Station, Derbyshire. 

 On reference to the pages of this /oiirnal, I notice a number of records of the white 

 form of this species taken in recent years, and for the sake of ready reference I 

 append the list, including a few records from other sources : — 1880. Rimmer, R. 

 "The Land and Freshwater Shells of the British Isles" [Went Vale, Yorks. 

 (Hebden) ; Reigate (Saunders)]. 1883. Hele, F. M. (Miss)^/. Conch., vol. 4, 

 p. 27 [One specimen found near Leigh Court]. 1885. Fitzgerald, H. Purefoy 

 — Id., p. 337 [Two specimens obtained at Preston Condover, N. Hants.]. 1887. 

 Pearce, Rev. S. Spencer—^. Conch., vol. 5, p. 255 [Taken on several occasions 

 during 1883, and again in 1887, in the vicinity of Wells, Somersetshire]. 1888. 

 Melvill, J. CosMO^;/. Conch., vol. 5, p. 316 [Two specimens in his collection 

 from Matlock, collected by Mr. Thomas Glover, of Manchester, who found a colony 

 of them on Aug. i6th, 1879]. i893- Milnes, Rev. Herbert — [. Conch., vol. 

 7, p. 278 [Matlock, one specimen (H. E. Craven) ; two specimens (T. Glover, 1879); 

 three specimens, (G. W. Chaster, 1892)]. 1896. Adams, Lionel E.—/. Conch., 

 vol. 8, p. 167 [One specimen collected by Mr. H. Westley at Ewell, near Dover, 

 in 1895]. Tom. cit., p. 228 [One dead specimen found by Mr. A. Loydell at 

 Brackley, Northamptonshire]. 1896. Adams, Lionel E. — " The Collector's 

 Manual of British Land and Freshwater Shells " [One specimen taken by himself 

 at Ewell, near Dover, on trunk of Birclv-; says form is rare]. 1904. Beeston, H. 

 and Wright, C. Yj.—J. Conch., vol. 11, p. 81 [Give the percentage of the white 

 form at Lynmouth as 3I per cent.]. Messrs. F. Taylor and T. Whitehead also 

 exhibited a number of this form from Lynmouth at the Conchological Society's 

 meeting in September, 1905. These were collected during the previous month. 

 Messrs. R. Standen and J. Ray Hardy both possess specimens from Matlock, 

 collected by Mr. Thomas Peace. It would appear from this list that the white 

 form has become more common in recent years, since, as pointed out by Mr. 

 Melvill ( /. Conch., vol. 5, p. 316) it was apparently unknown in this country when 

 Jeffreys published his " British Conchology " (1865). —J. Wilfrid JACKSO.^J {Read 

 before the Society, February 14th, 1906). 



