Freshwater Mollusca of Ireland. 31 
This very distinct and handsome species, both in form and colour, 
is common and universally distributed in Ireland. It affects situ- 
ations varying from very dry to very wet, and may be found on 
rocks, under stones, fallen leaves, &c., but seems rather to show a 
predilection for decaying wood. I have more than once detected the 
HZ. rotundata in company with Limaces banqueting on some of the 
larger Fungi. 
Specimens presenting much convexity are unfrequent, but in 
Shane’s Castle Park (county Antrim) a full-grown one has occurred 
to me, whose height was equal to its diameter. At Holywood House 
(county Down) I once obtained two specimens of the beautiful 
crystalline variety. The young of this species differ very much in 
form from the adult, in being quite flat above and very convex be- 
neath. In the stomach of a Blackbird (Turdus Merula), I once found 
ten full-sized specimens of this shell, in addition to five of Achatina 
lubrica. 
21. Helix umbilicata, Mont. p. 434. t. 13. f. 2. 
Zonites umbilicatus, Gray, Man. p. 166. pl. 5. f. 45. 
Helix rupestris, Drap. p. 82. pl. 7. f. 7—9; Turt. Man. p. 60. 
f. 45. ' 
Is commonly distributed throughout the southern three-fourths 
of Ireland, more especially over the great limestone belt which tra- 
verses the country :—‘‘at its eastern commencement near Dublin, 
and at its extreme western verge, where it dips into the ocean” in 
the South Islands of Arran, I have found it in equal abundance. 
This Heliz attaches itself more to one kind of rock limestone than 
any species hitherto treated of. With reference to what Montagu 
says of its habits, it may be remarked that I have commonly col- 
lected specimens on limestone debris resting on the ground and on 
loose stone walls or dykes. I have not seen any Irish specimens 
agreeing with Draparnaud’s figure in tapering to the apex* ; but all 
were of his var. “. testa subdepressa, umbilico latiore.”’ Mr. 
Gray’s figure, as above quoted, is characteristic of this form; in 
the Ist ed. of Turton’s Manual the other form was given. It is 
Drap. var. 6. only that Mr. Jeffreys quotes (Linn. Trans. vol. xvi. 
p- 348.), and it is this which Montagu describes ; his figure does not 
well represent either form. 
22. Helix pygmea, Drap. p. 114. pl. 8. f£.8—10; Turt. Man. p. 61. 
f. 46. 
Zonites pygmeus, Gray, Man. p. 167. pl. 5. f. 46. 
This species, so interesting from its minuteness, is indigenous to 
the more northern two-thirds of Ireland from east to west, and 
doubtless will be found by him who searches properly for it in the 
south. It is partial to shade and moisture, under stones in pastures 
may be procured, but is most readily and frequently obtained on fallen 
leaves, &c. in plantations. Since the Mollusca first claimed my 
* Draparnaud’s figure is very characteristic of specimens sent me from 
France by M. Michaud. 
