168 BRITISH MOLLUSKS. 



been collected in comparatively few localities, including Wales, 

 Westmoreland, and some parts of our southern and soutli-eastern 

 counties. 



8. Iiymnsea involuta. Involute Lymncea. 



Shell ; subtruncately ovate, bright yellowish horny, extremely thin 

 and transparent, submembranaceous, spire 

 small, immersed, whorls three to four, longi- 

 tudinally finely plicated, contracted round 

 the upper part, thin, convex, last whorl mo- 

 derately inflated ; aperture oblong-pyriform, 

 reaching to the plane of the apex, columella 

 thinly callous, hip very largely membrana- 

 ceously reflected over the body whorl. 



Limneus involutus, Harvey (1834), Trans. Linn. Soc. 

 vol. xvii. p. 559. 



Amphipeplea involuta, Thompson and Goodsir (1840), Ann. and Mag. 

 Nat. Hist. vol. v. p. 22. pi. i. 



Sab. Ireland. (In a small lake on Cromaylaun mountain, near the lakes of 

 Killarney.) 



This very interesting BullaAike Lymncea was discovered thirty 

 years ago by Professor Harvey in a mountain lake near the lakes 

 of Killarney. It is still, we believe, found in that locality, speci- 

 mens from which we have before us, and it has not been found 

 elsewhere. The animal has been described anatomically by Mr. 

 Groodsir. It is the same as that of L. glutinosa, and it produces 

 a shell in all respects similar except in the very peculiar contrac- 

 tion and immersion of the spire, which gives a more than usually 

 sinuous elevation to the aperture. It is of the same transparent, 

 membranaceous horny substance, similarly finely longitudinally 

 plicated, and it is characterized by the same broad and thinly ap- 

 pressed reflection of the columellar lip amalgamated, as it were, with 

 the body whorl. 



There is no satisfactory record of L. glutinosa ever having been 

 found in Ireland. Whether, therefore, L. involuta is a variety of 

 that species or not, its presence in that island is of the highest in- 

 terest. 



