GASTEROPODA. 307 



in the County of Kildare. From about Naas in the same County I have 

 been sujjplied with specimens by Dr. R. Ball ; and by the Rev. B. J. 

 Clarke with some obtained by him near Lea Castle, Queen's County. 

 County Kerry, Dingle, Rev. D. Foley, 1842. 



P. alhiis, Mull., 



Prevails generally over Ireland. Specimens of P. glaber, Jeffreys, 

 which I owe to the kindness of their describer, seem to me (as to Mr. 

 Alder) identical with P. albus. 



P. Icevis, Alder, 



Is found in the North-East of the island. Early in the winter of 1832 

 I obtained a number of this species on aquatic plants (especially Calli- 

 triche aquatica), with P. imhricatus, in a small pond at the Falls, near 

 Belfast, and about the same time procured others in the rejectamenta of 

 the rivers Blackstaff and Lagan, in the same neighbourhood. In the 

 demesne of Portavo, near Donaghadee, and also at Portmore, in the vici- 

 nity of Portaferry, localities in the County of Down ; it has likewise oc- 

 curred to me on Nymphaea and Potamogeton, 1846, Lang's Lake, near 

 Clogher, Mr. Waller. The animal is dark grey ; tentacula very pale grey 

 — dead shells are white. It was the P. Icevis which was marked with 

 doubt as "P. ylabcr? Jeff." in Phil. Mag. 1834, p. 300. 



P. imhricatusy Mull. 



This handsome and well-marked species is known to me as occurring 

 throughout Ireland, with the exception of the extreme South, where, 

 however, there is little doubt that it exists. It is very variable in form — 

 the varieties 1 and 2, and the " monstrosity with the volutions detached, 

 and raised above each other" (Turt. Man.), I have procured on the 

 same plant. The entire animal, together with the tentacula, are of a pale 

 grey colour. 



P. carinatus, Mull., 



Is much less common than P. marginatus, but found in all portions of 

 the island ; in the earliest catalogues it Avas inserted as indigenous. In 

 the neighbourhood of Portaferry, County Down, and about the city of 

 Dublin (a recorded locality), it has occurred to me. I have seen speci- 

 mens which were obtained near Portarlington by the Rev. B. J. Clarke : 

 at a lake near Tyrrell's Pass, Westmeath, by Mr. Ovens ; and at Lough 

 Gounagh (County Longford) by Mr. R. Callwell of Dublin.* 



In 1833 Dr. W. H. Harvey favoured me with specimens labelled "P. 

 planutus, Turt. Man.," from Portumna on Lough Derg, an expansion of the 

 Shannon, where he stated that the form was frequent, noting it at the 

 same time to have been found by him at Ballitore (County Kildare), 

 where it is very rare ; these shells correspond exactly with Turton's de- 

 scription of P. plcumtiis, Man. p. 110. This seems to be the common form 

 (though the normal one does likewise occur) at Lough Derg, as testified 

 by specimens since obtained from Portumna and Killaloc, near its north- 

 ern and southern extremities ; some from Nenagh (County Tipperary) 

 have been kindly submitted to my inspection by the Rev. T. Hincks of 



* The size is, I conceive, attributable to the coldness of (he wafor and 

 scarcity of subaquatic plants. 



