82 JOURNAL OF CONCHOLOGY. 



CONTRIBUTIONS TOWARDS 

 A LIST OF NORTH WILTSHIRE MOLLUSCA. 



By T. D. a. COCKERELL. 



The recorders of the Conchological Society, in their annual 

 report, observe that only one county in England, North Wilts., 

 is without any records whatever. Having recently spent a few 

 days at Swindon, I therefore endeavoured to collect as many 

 species as possible, and am able to offer the following list as a 

 nucleus to which we may hope, in the course of time, to add 

 greatly, but which may serve as a first indication of the nature 

 of the molluscan fauna. 



Sph^rium corneum. 



S. lacustre. Type. 



S. lacustre var. ryckholtii. All these in the same pond, 

 but the two species were in different parts of it. The type 

 of S. lacustre was very common at one place, but only one 

 of var. ryckholtii was found (measuring 6x6 mill.). 



Pisidium fontinale. In a pond, with ^. cortieiwi. 



P. pusillum. In a small pond. 



Unio tumidus. A single valve in the canal at Swindon. 



Bythinia tentaculata. 



Planorbis fontanus (^=nitidus Jeff). With B. tentaculata 

 in a pond, and elsewhere ; apparently a common species 

 in the district. 



P. albus var. major. One found in a pond : the variety is 

 new to Britain. Locard, in 1879, gives the diameter as 

 4 — 6 mill, and Pascal, in 1883, gives the diameter as 

 7 mill., alt. I J mill. My specimen from Swindon has 

 diam. 7^ mill., alt. 2 mill, 



P. vortex. 



P. contortus. Living in a pond, with P. vortex. 



J.C, v., July, I8S6. 



