13 

 PisiDiUM ciNEREUM. Alder. 



This species is next, in point of size, to Pisidium 

 amnicum. It is rather compressed in its form. The 

 epidermis is shining, and of a greyish colour. The um- 

 bones are broad. Its length is one-fifth of an inch, and 

 its breadth near two lines. 



An inhabitant of ponds. 



Pisidium cinereum is placed amongst our Notting- 

 hamshire shells on the authority of JeflPreys, who dis- 

 covered it in Clumber Lake. I have not as yet found 

 it. The recorded localities are, north of England 

 (Alder), Preston (Gilbertson), Scarborough (Bean), 

 Croydon Canal and near Swansea (Jeffreys), Bath and 

 Exmouth (Clark). It is not common, though generally 

 distributed, in Ireland (Thompson). In Scotland, Bal- 

 macarra, West Ross (Jeffreys). 



Forbes says it is an inhabitant of Sicily. 



Pisidium Henslowiandm (The Appendiged Pera). 



Sheppard. 



This shell differs but little from Pisidium pulchellum, 

 excepting in the curious eave-like projections on the 

 umbones, which P. pulchellum has not. The shape is 

 obliquely ovate, The extreme size is 2| lines in length , 

 and 2 lines in breadth. 



Everywhere this is a rare shell. It is met with in 

 rivers and ditches. 



I have included it in this catalogue from one speci- 

 men only, which was found in a moist ditch, along 

 with other Pisidia, near Beeston Railway Station. 



Other localities given are, ditches running into the 



river Cam, at Cambridge (Prof. Henslow), also a few 



miles below Cambridge (Jenyns), in the river Thames, 



near Henley (Strickland), near London (Grey), Kent 



c 



