8TKLFOx~Lisi of Land and Freshtvater MoUusks of Ireland. 12;5 



From the extreme soutli and south- 

 east we have as yet no reooids ; hut it 

 should certainly occur in the latter 

 district. The prevailing form is small, 

 7 inches heing about the maximum 

 length. This size is attained only in 

 specimens from canals and the smaller 

 lakes. Shells found in the larger lakes 

 seldom exceed 4 inches. M. Henri 

 Drouet has identified the large form 

 found in the Eoyal Oanal as A. cijgnea, 

 but considered the smaller to belong to 

 A. ceUensis Schroter. 



the lakes of the limestone area, which 

 is very globose and with large, 

 prominent umbones. 



Note added in Peess. — I have re- 

 cently taken some exceedingly small 

 examples of a Sphaeriuiii in "West Mayo. 

 These, although apparently well grown, 

 are smaller than the fry of S. corneum ; 

 but until I have obtained more specimens 

 and further investigated the matter I 

 cannot say whether they belong to this 

 species or not. 



GYRENIDAE. 



Sphaerium corneum (Linne). 



Tellina cornea, Brown, 3Iem. Werner. 

 Soc, vol. ii, p. 508, 1818. Cyclas 

 cornea, Thompson, Cat. L. & I". W. 

 Moll, of Ireland, p. 38, 1840. 



WD ED LD AN 

 FE TY AR DO 

 WMSL LE MO 



EM RO CV LH 

 WG NG LF WH ME 

 SG KG KD OU 

 CL NT QG CW Wl 

 NK LK ST KK WX 

 SK MG EG WA 

 wc 



Generally distributed, but absent 

 from, or extremely rare in, the south- 

 west and north-west, rare in most of 

 the western counties, and not recorded 

 for any of the western islands. In 

 reality it is a "central" specdes, with 

 a somewhat extended range. Many 

 forms occur ; bnt the most important 

 variation is that met with in some of 



Sphaerium lacustre (Miiller). 



Cyclas lacustriis, Thompson, Cat. L. & 

 F. \Y. Moll, of Ireland, p. 38, 1840. 



WD ED LD AN 



FE TY AR DO 

 WMSL LE MO 



EM EO CV LH 

 WG NG LF WH ME 



SG KC KD DU 

 GL NT QC GW W! 

 NK LK ST KK WX 



BK MG EG WA 



WC 



Has a distinctly eastern range, and 

 is found in all the eastern maritime 

 divisions. It iilso occurs in the southern 

 divisions of the central plain and as far 

 west as Clare and JTorth-east Galway. 

 It is always a local shell, but generally 

 common wliere it is to be found, and in 

 Lough Neagh, at the inlets of some of 

 the larger rivers, it occurs in enormous 

 numbers. Here during certain seasons 

 it may be dredged in bucketful?. 



