54- LAND AND FUESII-WATEK MOLLUSKS. 



a likely thing that any bird should use the same amount of force as he was 

 obliged to do. 



Loose bits of the plant floating down, and so being picked up, is certainly a 

 question, and one I should much like to see worked out.""' It is a strange and 

 almost an incredible tale, that, a little weed first discovered in 1841, and sup- 

 posed to have been accidentally introduced, should now in 1852 threaten to 

 interrupt the navigation of our rivers and canals. So true is it that, "Multa 

 minuta magna oflSiciunt." 



Christ Gollccje, Cambridge^ Novemher, 1852. 



A LIST WITH NOTES ON THE HABITATS AND 



LOCALITIES OP THE LAND AND FRESH-WATER MOLLUSKS, 



OBSERVED IN THE VICINITY OF LEWES, IN SUSSEX. 



fiV W. C. L'NWIX, ESQ. 



It has somewhat surprised me when reading the various interesting and 

 instructive Papers and Notices in ''The Naturalist," upon almost every other 

 subject in Natural History, to find how rarely we meet with any such exclu- 

 sively devoted to our Land and Fresh-water Molluslcs, considering how much 

 this hitherto neglected branch has of late advanced, and is daily becoming 

 more and more cultivated. 



With this impression I venture to claim the indulgence of its readers to 

 a brief account of the habitats and localities of some of the objects of this 

 truly engaging and healthful pursuit, as they have been observed and collected 

 by me in this neighbourhood, with the hope that it may induce some other votary 

 to add a similar one of his district* for by this means we shall, if I may so 

 speak, become acquainted with the comparative climatal and geographical range 

 of the species. 



The Nomenclature is from Gray's Edition of Turton, (1840.) 



Bithinia tentaeulata, Oray. — Very common in the levels. 



Bithinia ventricosa. Gray. — Not uncommon in the ditches by the side of 

 Kingston road. 



Valvata piscinalis. Lam. — In every ditch very common. 



Valvata cristata. Mid. — In a ditch near the Cockshat: somewhat rare. 



Arion ater. Gray. — In the brooks: common. 



Limax maximus, Linn. — In gardens and cellars, ete. 



Limax agrestis, Linn. — Common everywhere. 



Limax flavus, Linn. — By the side of a ditch near the Priory. 



* Since writing the above I have had the pleasure of seeing Professor Henslow, and on asking 

 him how the Anacharis has hecome so' abundant, and likewise how it has found its way into 

 80 many different waters; he informed me that every separate whorl is capable of throwing 

 out roots from its axis, and thus of becoming a distinct j'lant. Such being the case, birds and 

 even beetles may' convey the small portion necessary for the production of a perfect plant to 

 the diffei'cut streams. 



