144 JOURNAL OF CONCHOLOGY, VOL. l6, NO. 5, JANUARY, I92I. 



Sphaerium lacustre (Miiller).— Rare. Pond at foot of De- 

 ganwy Hill, 1877 ; pond, Abbey Road (none now, 1915). 



The paucity of freshwater species is owing to the lack of streams, 

 ponds, etc., in the district. There was a time when the Morfa no 

 doubt had many wet ditches, but these no longer exist, and the only 

 drain of importance left is choked with rubbish and foul. 



Limnaea stagnalis destroyed by Rats. — Whilst searching for specimens 

 along the banks of a pond near Ashley Mill (Cheshire) during 1919, I came across 

 two or three small pockets or hollows filled with the dead and damaged shells ot 

 Limnaa stagnalis. On examination I found these had all been broken in a similar 

 manner, a portion of the body whorl having been removed by some creature, 

 evidently with the object of devouring the animal. I visited the spot on several 

 subsequent dates, and discovered further larders, one of which was situated in a 

 tuft of rushes, and contained over fifty dead shells. The water at the edge of the 

 pond near these larders is very shallow and full of weed, and in season literally 

 alive w'ith scores of L. stagnalis in all stages of growth. An examination of the 

 soft mud showed the footprints of rats, whilst a well-worn track led from the 

 water's edge to the large larder already mentioned. As the water-vole is sup- 

 posedly a vegetable feeder and has not been observed on this pond, whilst rats 

 are commonly seen around it, the evidence is sufficiently strong to point to the 

 latter as the enemy which is destroying large numbers of this mollusc. — A. K. 

 Lawson. {Read before the Society, February llth, 1920). 



Clausilia biplicata Mont, in Essex. — I am glad to be able to record a new 

 station for this extremely local British mollusc. When on my way to Grays, Essex, 

 on September 5th last, in order to search for Assiniinea grayana and other brackish 

 water species which occur there, I took the opportunity of visiting Purfleet in 

 order to explore the large chalk pit there. Finding it inipossible to do so, how- 

 ever, owing to its occupation by the military, and having some time to wait on 

 getting back to the railway station, I commenced to search a somewhat unlikely- 

 looking chalky bank in its vicinity, when, much to my surprise, I almost at once 

 turned out an example of Clausilia biplicata from amongst the chalk debris. 

 Further search revealed the presence of a fair-sized colony, including young and 

 dead shells. Assuming this is not an introduction by some conchologist (I know 

 of no one likely to have introduced it), the species is an addition to Mr. Wilfrid 

 Mark Webb's excellent county list (The Non-Marine Mollusca of Essex, Essex 

 Naturalist, 1896, pp. 27 —48 and 65 — 81), and the locality is also a considerable 

 extension of its hitherto known range in the Thames Valley. I think it as well to 

 take this opportunity of calling attention to a record of CI. biplicata from Glou- 

 cestershire (Leckhampton Hill) which appeared in S\\\% Journal for 1913 (vol. 14, 

 p. 57), as this owing to its having been included without remark in a list of 

 census records is very likely to be overlooked. I think it would have been better 

 in the case of a species with such a restricted British range if this record had 

 been made the s ubject of a separate note. — F. B. Jennings, ist January, 1920. 

 {Read before the Society, February nth, 1920). 



