120 



Proceedinfjs of the Eoijal Irish Academi/. 



on the coasts of all four jiro'nnces. 

 Shows great variation in size and 

 shape, in the depth of suture and other 

 characters. 



Bithynia tentaculata (Linne). 



HeJix tentacidata, Brown, Mem. TTemer. 

 Soc, vol. ri, p. 531, 1818. Paludina 

 tentamdata, Thompson, Cat. L. & 

 F. W. Molhisca of Ireland, p. 3, 

 1840. 



WD ED LD AN 

 FE TY AR DO 

 WMSL LE MO 



EM RO CV LH 

 WG NC LF WH ME 

 SO KG KD DU 

 GL NT QG GW Wl 

 NK LK ST KK WX 

 i^K MG EC WA 

 WG 



Common over the gieater part of the 

 country, but becoming scarcer in all 

 directions away from the central plain, 

 and absent from districts such as "West 

 Donegal (metamorphic area), Antiim 

 and Derry (basaltic plateau), West 

 Mayo (metamorphic area), and the 

 mountainous parts of Cork and Kerry. 



Bithynia leachi (Sbeppard). 



The distribution of this shell greatly 

 resembles that of several of the 

 "central" species; but it has not so 

 extensive a range as Phnolis vortex, 

 or as Neritina fuviatilig. The centre of 

 its distribution is worth noting, being 

 close to the only Irish, stations for 



Planorlis comeus. The similarity of the 

 geographical distribution of these two 



WD ED LD AN 



FE TY AR DO 

 WMSL LE MO 



EM EO CV LH 

 WGNG LF WHME 



SO KG KD DU 



CL NT QC GW WI 



NK LK ST KK ^'-'^ 



SK MC EC WA 

 WC 



shells has already been pointed out by 

 Mr. Welch (Irish Is'at., p. 1, 1908). 



YALYATIDAE. 



Yalvata piscinalis (Miiller). 



Plate VII, figs. 27, 28. 



Turbo fontinalis, Brown, Mem. Werner. 

 Soc, vol. ii, p. .522, 1818. 



WD ED LD AN 

 FE TY AR DO 

 WMSL LE MO 



EM RO GV LH 

 WC NG LF WH ME 

 SG KG KD DU 

 GL NT QG GW Wl 

 ^K LK ST KK WX 

 SK MG EC WA 

 WG 



Generally distributed, and common 

 in almost all parts of the mainland, and 

 occurs on Clare Island in West Mayo. 

 The prevailing fonn according to 

 Mr. Eennard is that known on the 

 Continent under the specific name of 

 Valvata alpedris. Blauner. (Fig. 27.) 



