Freshwater Mollusca of Ireland. 123 
the Falls, near Belfast, and about the same time procured others in 
the rejectamenta of the rivers Blackwater and Lagan, in the same 
neighbourhood. In the demesne of Portavo, near Donaghadee, and 
in the vicinity of Portaferry, localities in the county of Down, it has 
likewise occurred to me. The animal is dark gray ; tentacula very 
pale gray—dead shells are white. It was the P. levis which was 
marked with doubt as “‘ P. glaber? Jeff.” in Phil. Mag. 1834, p. 300. 
4. Planorbis imbricatus, Mull. Gray, Man. p. 261. pl. 8. f. 94; 
Turt. Man. p. 111. f. 94; Drap. p. 44. pl. 1. f. 49—51. 
P. cristatus, Drap. p. 44. pl. 2. f. 1—38. 
Helix nautileus, Mont. p. 464. t. 25. f. 5. 
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 gray colour. 
5. Planorbis carinatus, Mull. Gray, Man. p. 262. pl. 8. f. 89; 
Turt. Man. f. 89; Drap. p. 46. pl. 2. f. 13, 14, 16. 
Is much less common than P. marginatus, but found in all por- 
tions of the island—in the earliest catalogues it was inserted as in- 
digenous. In the neighbourhood of Portaferry, county Down, and 
about the city of Dublin (a recorded locality), it has occurred to me. 
I have seen specimens which were obtained near Portarlington by 
the Rey. 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 Dublint. 
In 1833 Mr. W. H. Harvey favoured me with specimens labelled 
*« P. planatus, 'Turt. Man.,” from Portumna on Lough Derg, an ex- 
pansion 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 ex- 
actly with Turton’s description of P. planatus, 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 Killaloe}, near its northern and southern extremities 
—some from Nenagh (county Tipperary ) have been kindly submitted 
to my inspection by the Rev. T. Hincks of Cork; near this city the 
“« P. planatus” is noticed by Mr. Humphreys as met with. Mr. Al- 
der and Mr. Forbes consider the Lough Derg shell P. carinatus, 
and, according to the former, it is the P. disciformis, Jeff. 
+ Mr. Edw. Waller has favoured me with marl shells of this species from 
Finnoe, and remarks that it is the only shell found there in mar! that is not 
to be had in a living state; but this he attributes to the draining of a marsh. 
{ To the kind attention of Mr. John J. Marshall of the former, and the 
Rev. C. Mayne of the latter place, I am indebted for them. 
