147 



LiMN^us PALUsiRis [The Ditch Mud Shell]. Linnceus. 

 Figures 108 and 109. 



109. 



A thick, strong, and lengthened oblong shell, wiih a 

 spire tapering to a point. There are seven swollen 

 convolutions, with suture deep. Nearly opaque. Minute 

 umbilicus. Aperture suboval, and usually pink inter- 

 nally. Brownish horn-coloured. 



Very variable in size ! the largest specimens are an 

 inch and a quarter in length, and 6^ lines wide. The 

 finest specimen from Sawley did not exceed an inch in 

 length. 



The animal is of a leaden-black colour. 



Described by Lister in 1678. 



A widely spread species. Found in ponds, ditches, 

 and marshes, mostly crawling on the wet mud close to 

 the water. 



It lays from 60 to 80 eggs at one time. 



There are several varieties, the most distinct being 

 the var. tinctus of Jeffrey , it is less in size, the spire 

 shorter, wide, and the suture shallow. This variety is 

 found sparingly at Lenton and Beeston. Ver^ similar 

 specimens have been sent by Mr. Jefl'reys from Swansea. 



The Nottinghamshire localities are Beeston Rye- 

 lands, Thrumpton, Lenton, and Sawley ; in the latter 

 locality it is very common and large. 



The more distant localities which may be mentioned 

 as examples are — Land's End, Cornwall (Millett), 



