144 JOURNAL OF CONCHOLOGY, VOL. II, NO. 5, JANUARY, I905. 



endowed with much greater power of dispersion into new areas than 

 Others. Hardy forms, like Helix fiemoralis, probably spread very 

 much more rapidly than species like Helix fusca, which is confined to 

 damp and shady glens and woods, so that the latter with a rather 

 local range might yet be an ancient species. 



To judge from the present and past range of our land and fresh- 

 water moUusca, I think we may safely conclude that they have 

 originated in widely-separated areas of our globe, and have found 

 their way to these islands by different routes. How long they have 

 lived in this country it would be difficult to estimate. It is quite 

 possible, however, that some may have come in early Tertiary times, 

 when the distribution of land and water was vastly different from 

 what it is now. 



It was not my intention, in the limited time at my disposal, to give 

 you a complete survey of the history of our land and freshwater 

 moUusca. I merely wished to acquaint you with my views as to the 

 manner in which this study should be prosecuted. No one has as 

 yet worked out the problem with the amount of research and investi- 

 gation that the subject demands. It is certainly a most complex 

 problem, the solution of which will require years of painstakihg 

 thought and study. If my address has awakened, in the younger 

 members especially, a desire to take up this enquiry, I can assure 

 them that they will find it most fascinating, and I should feel also 

 that my object of presenting these few notes to you has been amply 

 fulfilled. 



Vivipara contecta var. atro-purpurea nov. at Wicken Fen, Cambs. — 



Whilst collecting shells at Wicken Fen, Cambridgeshire, in August, 1889, and 

 August, 1900, I found a few Vivipara contecta, about one-half of which were 

 bandless and of a uniform dark-purple colour, and during August of the present 

 year in the pit-holes on the " Poor Man's Land," Wicken Fen, I again found the 

 same form along with the type. The nepionic whorls in these bandless specimens 

 are bright translucent white, striated faintly, and contrasting strongly with the dark 

 colour of the rest of the shell. As this dark-purple form does not appear to have 

 been previously noticed, I have pleasure in proposing the varietal name atro- 

 pu7-purea, to which variety of V. vivipara it corresponds. — Fred. Taylor {Read 

 before the Society, October 12, 1904). 



Limnaea stagnalis var. umbilicata. — A specimen of Linincea stagnalis col- 

 lected by me from a pond at Bell Isle, near Leeds, on the 25th of October, 1904, 

 shows the mouth of the shell differing very much from the type, being more elon- 

 gated with a slight bulging in of the centre of the outer lip ; the shell has also a 

 small umbilicus into which I inserted a bristle to the depth of rtrths of an inch and 

 in some cases a quarter of an inch. Out of a dozen shells collected, all had the 

 mouth of the shell thus modified, and all the large ones, with the exception of two, 

 the small umbilicus. I have shewn specimens to Mr. Taylor and Mr. Nelson, of 

 Leeds. — W. Harrison Hutton {Read before the Society, November 9th, 1904). 



