107 



of Draparnaud, and its allied forms, would legitimately 

 constitute a distinct species ; but, after a very careful 

 and protracted comparison of many hundred specimens, 

 I could not satisfactorily separate them from interme- 

 diate varieties. The difference in the colour of the body, 

 as well as in the consistency and even the shape of the 

 shell, appears to depend on the nature and quantity of 

 the food, the chemical ingredients of the water, and the 

 degree of stagnation or rapidity of its current. M. Mo- 

 relet, in his description of the Portuguese land and fresh- 

 water Mollusca, says, with much naivete', of the L. inter- 

 media, " aussi reconnaissable que puisse l'6tre une espece 

 dont le caractere principal est de n'en point avoir." The 

 difficulty of admitting or rejecting such forms as specific 

 is quite as great as in the case of Anodonta. I have 

 merely noticed some of the more peculiar varieties of the 

 present species. 



L. peregra is not very slow in its movements. It is 

 nearly amphibious ; and, as its name imports, it is fond 

 of wandering and seeing a little of the world, being 

 occasionally met with at some distance from its native 

 element in a damp meadow or climbing up the trunk of 

 a willow-tree. This habit reminds one of the inland 

 travels of the Perca scandens. An interesting account 

 of the floating voyages made by our molluscan traveller 

 on an old canal near Inchbroom will be found in the 

 Rev. Dr. Gordon's Contributions to the ' Zoologist.' He 

 says that when the shoal of L. peregra had fairly started, 

 they resembled a fleet of herring-boats in miniature. 

 This mollusk is very prolific and lays about 1300 eggs 

 in a season, contained in clusters of from 12 to 180. It 

 is zoophagous, as well as phytophagous ; and a writer in 

 the ' Zoologist ' lately stated (p. 7400) that it ate min- 

 nows when they were confined together in an aquarium. 



