122 CYCLADIDvE. 



measuring a lino and three-quarters in length, and a line 

 and a half in breadth. 



The animal, according to Mr. Jenyns, is white. Its 

 siphonal tube is abbreviated and more subconic. The 

 foot is more than half the length of the shell. 



" It occurs not unfrequently in Cambridgeshire, inhabit- 

 ing small splashy pools and other stagnant waters,'' 1 and is 

 likewise taken in Surrey (Jenyns). 



In Ireland it is by no means common, but is recorded to 

 have been taken in Down and Tipperaiy ; in the latter at 

 Finnoe, in the former from a pond at Portavo, and from a 

 drain in the clay-soil of a brick-field near Bangor. (Thomp. 

 Ann. N. H. vi. p. 195.) K. Mancey (Mr. Bailee). 



Mr. Jeffreys and Mr. Barlee procured it from Balma- 

 carra in W. Ross ; and Captain Brown, who first an- 

 nounced it as British, found it under the columnar greenstone 

 rocks, at the west end of Arthur's Seat, near Edinburgh, 

 and plentifully in a ditch (now covered up by the railway) 

 at the Wells of Weary. Mr. Jeffreys once dredged a 

 dead specimen of this species in forty fathoms water off 

 Tarbet in Loch Fyne, to which extraordinary locality it 

 had probably found its way in consequence of having been 

 washed into the water by a stream. 



From the delineation by Delessert of the Lamarckian 

 example of Cyclas ohtusalis we ascertain with certainty 

 (what was previously suspected), that our own species is not 

 precisely identical with Lamarck's, which, if any of our 

 British shells (the description is most inadequate, and no 

 locality is cited), is probably pus'illum. Pfeiffer seems to in- 

 dicate our typical form, and Nilsson the produced variety. 



