4332 Mollusks. 



List of Land and Fresh-water Mollusks found near Sevenoaks, 

 Kent. By R. H. S. Smith, Esq. 



As several local lists of land and fresh-water Mollusc a have from 

 time to time appeared in the ' Zoologist,' and have been examined 

 with much interest by many others as well as myself, I have fre- 

 quently wished to offer my contribution to this interesting department 

 of Natural History. But the unwillingness, which collectors will 

 understand, to publish a list before sufficient efforts had been made 

 to render it complete, has hitherto delayed me, and even now, although 

 the number of species is considerable, I expect future researches to 

 be well rewarded. 



A glance may be permitted at the geological character of the 

 district to which my list refers, — always a matter of interest to the 

 collector of inland Mollusca. It lies partly upon the southern aspect 

 of the lower chalk formation, where it unites with the weald clay ; 

 and thus presents chalk, chalk-marl, green sand, ironstone, plastic, 

 and other clays : but, owing to the dry nature of much of the soil, 

 many of our Mollusca are but thinly represented. The small river 

 Darent is distant about two miles, and, with the ditches near it, has 

 afforded several species. A few have been obtained from a wider 

 range. The nomenclature is that of Gray's edition of 'Turton's 

 Manual.' 



Bithinia tentaculata. Frequent in ditches near the Darent. 



„ ventricosa. The Medway, near Maidstone. 

 Valvata piscinalis. The Darent and ditches near it ; not abundant. 



„ cristata. Same localities; rare. 

 Arion ater. Common, exhibiting the usual varieties of size and 

 colour. 



„ hortensis. Not so frequent as the last. 

 Limax maximus. Not uncommon. 



„ agrestis. Common. 

 Vitrina pellucida. Frequent. I have one specimen considerably 

 larger than ordinary, not transparent, and exhibiting a pearly lustre 

 within. 



Helix aspersa. Abundant. 

 „ hortensis. Abundant. Varying much in colour and mark- 

 ings, yet preserving the distinctions which seem to separate it from 



