FRESH-WATER SHELLS. 2$ 



had been dry for three years at a stretch ; when the 

 water reappeared in the fourth year the little mollusc 

 seemed as abundant as ever. Lhnncea parva, also, was 

 seen by the same naturalist in considerable numbers 

 about the margins of small basins which had been dry 

 for three or four years.^ Mr. W. Jeffery, in a paper on 

 the mollusca of Western Sussex, remarks upon the 

 presence of LimncBa tmncatida wherever a roadside 

 stream trickles down in spring, no matter at what 

 elevation, and notwithstanding the fact that the water 

 is almost sure to be dried up in summer, and he 

 mentions having seen specimens in a marl-pit far from 

 any permanent water." Mr. H. C. Leslie has recorded 

 the finding of about half-a-dozen full-grown specimens 

 of LimncEa peregra in a puddle, containing some two or 

 three gallons of water, formed by the breaking out of a 

 small spring by the roadside on one of the hills near 

 Erith/ and the same species has been noted by Mr. 

 Roebuck as common in roadside puddles between the 

 Orme's Heads, and elsewhere, in Wales.^ Sir C. Lyell, 

 in one of his published letters, states that " Lymnea 

 truncatella," introduced unintentionally by the Por- 

 tuguese into Madeira, went all over the island in thirty 

 years, and was said to have appeared even in pools and 

 ruts in the roads ; if this be so, he adds, the creature 

 has powers of spreading "which require investiga- 



^ W. A. Marsh, " Conchologists' Exchange," ii. (1888), no. 



' W. Jeffery, " Journ. of Conch.," Hi. (1882), 311-12. 



3 H. C. Leslie, "Science Gossip," 1870, p. 137. 



* W. D. Roebuck, "Journ. of Conch.," iv. (1884), 209. 



