LIMNiEA PEREGRA. 151 



painstaking naturalist, refers the Litnneus aciitus of Jeffreys to 

 Limnceus peregra var., whilst I think that most conchologists would 

 agree with Dr. Jeffreys, and refer it, as he did later, to L. auri- 

 cularia. 



Von Maltzan unites L. peregra with L. aiiricularia. It cer- 

 tainly comes very near to L. lagotis, some of the numerous 

 varieties of which can scarcely be separated from Z. peregra. 



Litnncea peregra has been found in a fossil state in the Mam- 

 malian Crag at Southwold and at Bramerton, also at Stutton and 

 at Clacton. It is often found in a sub-fossil state, as at Askern, 

 and in the banks of the Tutt at Staveley. Mr. Roebuck found 

 fossil specimens in the mud cliffs at Hornsea, whilst myriads of 

 this species are turned up by the drainers at Silverdale. 



[n a living state it occurs in rivers, streams, ditches, ponds, 

 and lakes, at all elevations, from mountain tarns down to the 

 brackish water on the sea beach, being found in ponds within 

 reach of the spray from the sea-waves. A variety of it was collect- 

 ed by Dr. Hooker on the Thibetian Himalaya, at an elevation of 

 18,000 feet. 



It is very generally distributed over the whole of the British 

 Isles, throughout Europe, Afghanistan, Siberia, and throughout 

 North America, under the name of L. colmnella and many other 

 synonyms. It has also been found in Tasmania and described by 

 Rev. E. Tenison Woods as Limncea hobartonensis, L. huonensis, 

 L. launcestoniensis , and lastly, a few years ago Dr. Edward Atkin- 

 son kindly presented me with a few freshwater shells, sent to him 

 direct from a place called Tsing-fu-chu in North China, amongst 

 which I was pleased to find our old acquaintance, L. peregra. 



In some cases it is very difficult to account for the local dis- 

 tribution, seeing that it is almost invariably the first species to 

 make its appearance in a new pond, as, for example, brick ponds, 

 in situations where no flood water can reach, and near large towns, 

 which are not likely to be visited by aquatic birds bringing a 

 supply of young fry attached to their feet. 



A few curious cases have been recorded of how they might 

 become distributed. Mr. W. Thompson, in 1841, mentioned that 

 he once saw a number of L. peregra attached to the backs of 

 some turtles kept in a pond at Fort William near Belfast, and they 



