Freshwater Mollusca of Ireland. 119 
Michaud, in acknowledging the receipt of specimens from Lough 
Neagh, remarked that the form was unknown to him in France. 
I have seen the L. pereger attached in numbers to the backs of 
turtles, kept in a pond at Fort William, near Belfast, when it was 
amusing to observe these animals swimming about, with the Limnei 
still keeping “ their seats’ upon them. 
3. Limneus involutus, Harvey. 
Amphipeplea involuta, Gray, Man. p. 245. pl. 12. f. 147. 
This Limneus so remarkable in form was discovered by Wm. H. 
Harvey, Esq. in a small lake on Cromaglaun Mountain near the 
lakes of Killarney. A description of it will be found in the Annals 
Nat. Hist. for March 1840, p. 22. Its specific character is—spire 
sunk within the outer whorl; aperture very large, extending to the 
apex. 
4. Limneus stagnalis, Drap. p. 51. pl. 2. f. 38, 39; Gray, Man. p. 
236. pl. 9. f. 104; Turt. Man. p. 121. f. 104; Rossm. f. 49. 
Helix stagnalis, Mont. p. 367. t. 16. f. 8. 
This, the largest European Limneus, though by no means gene- 
rally distributed, occurs in every portion of the island. It differs 
very much in size, according to locality ; mature specimens, which | 
have found in the cold water of Lough Neagh, where barren of sub- 
aquatic plants, did not exceed one inch in length, whereas in drains 
in which such plants abound, they attain double this size. 
A Limneus collected by my friend Richard Langtry, Esq., of Fort 
William, near Belfast, when on a tour through Upper Canada in 
1835, seems identical with L. stagnalis. It differs from the ordinary 
form only in tapering rather more towards the apex, and in the second 
largest volution being a little more tumid; but in these respects an 
extensive series of Irish specimens before me differ very much. The 
American specimens were taken in the river connecting Buckhorn 
with Pigeon Lake. 
5. Limneus palustris, Drap. p. 52. pl. 2. f. 40 —42. and pl. 3. f. 1, 2; 
Gray, Man. p. 239. pl. 9. f. 107; Turt. Man. p. 123. f. 107; 
Rossm. f. 51, 52. 
Helix palustris, Mont. p. 370. t. 16. f. 10. 
Common, and generally distributed over Ireland—in size, form, 
and colour very variable. In the river Bann, near Kilrea, I have 
procured specimens of the ordinary colour, but with the addition of 
spiral narrow white bands—in some waters the different species of 
Limnei, &c., are so marked. A shell differing from the L. palustris 
in general proportion (being much shorter relatively to its breadth) 
and in colour (generally of a uniform pale yellow), is common to 
Cumberland.”” Manual, p. 236. This erosion is but too common in the 
specimens I have eollected in Ireland, but was always attributed by me 
simply to the progress of decay, the shells having for some time been ex- 
posed on the beach. When the tips were eroded the shells always presented 
other marks of decay. 
