THE MOLLUSCA. 133 



brown in colour, with a narrow yellow band round the 

 margin. 



Cyclas cornea (Horny Cycle). In almost any ditch. A round 

 and dumpy shell, generally dark brown, varying in size 

 from one-eighth to half an inch in diameter. 



Cyclas calyculata (Capped Cycle). Found sparingly in a 

 stream by the first bridge beyond Churchtown, along the 

 road to Martin Mere. A very transparent shell, about a 

 quarter of an inch long ; the umbones the parts above 

 the hinge very prominent. 



Pisidium amnicum (River Pera). Not uncommon in ditches 

 on the Moss, and on the Martin Mere road, beyond 

 Churchtown, but very small, rarely measuring more than 

 one-eighth of an inch long; common and very fine in the 

 canal at Burscough Bridge. In shape obliquely oval, 

 with minute raised ribs. 



UNIONID.<E. 



Anodonta cygnea (Swan Fresh-water Mussel). Common in 

 many of the streams and ditches on the Moss, varying 

 from two to four inches in length, oval in shape, olive or 

 brown outside, bright pearly within. One of the largest 

 and handsomest of the British shells. 



GASTEROPODA PR OSOBRA NCHIA TA. 



PALUDINID^E. 



Paludina Listen (Marsh Shell, or River Snail). Not uncommon 

 in many of the ditches on the Moss. At the approach of 

 winter it buries itself deep in the mud, and makes its 

 appearance again with the warm days of April. A very 



