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. pi. 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. pi. 2. f. 38, 39; Gray, Man. p. 



236. pi. 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 I 

 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. pi. 2. f. 40 — 42. and pi. 3. f. 1, 2 ; 



Gray, Man. p. 239. pi. 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, Sec, 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 collected 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. 



