129 



Draparuaud, Miiller, Turton, Lamark, Pfeifl'er, Bro\vn, 

 Braid, &c. It was first described by Boys, in the year 

 1784. 



A delicate, minute, depressed, born-coloured shell, 

 often covered with a black incrustation. Upper disc 

 flat, lower disc convex. Aperture ovate and entire. 

 There are three convolutions, the outer edge of the 

 body whorl being mostly imbricated with membraneous 

 ridges. Diameter of the shell from an eighth to a 

 tenth of an inch. 



The colour of the animal is light grey. 



Variety cristatiis of Draparnaud is smaller, and the 

 transverse laminoe are wider. 



It lajs six eggs (Chauteieaux). 



A widely spread mollusc, found upon aquatic plants 

 and decayed leaves in ponds and ditches. 



Specimens sent by Mr. Bean from Scarborough and 

 by Mr. Jeffreys from Swansea did not differ from those 

 procured here. 



It is found in the lake at Highfield House, and in a 

 marl-pit at Stanton-on-the-Wolds ; in neither place 

 abundant. 



Other recorded localities are— Penzance (Miliett), 

 Dorsetshire, 'Wiltshire, and Kent (Montagu), Bristol 

 (Miller), Essex (Sheppard), Norwich, rare (Bridaiman), 

 London (Grey), Scarboroiigb (Bean), Lytham, rare 

 (The Author), Kendal (Gough), Newcastle (Alder). 



In the south and middle of Scotland (Forbes), Aber- 

 deen (Macgillivray), Ireland (Brown), Isle of Man, rare • 

 (Forbes). 



On the continent, in France (Draparnaud), in Ger- 

 many (Pfeifler), and in Sweden (Nilson). 



Found fossil in the mammaliferous crag near London 

 (Morris). 



