1907 4 1 



LAND AND FRESH-WATER MOI^USCA. - 



BY A. W. STEI.FOX AND R. WELCH, M.R.I.A. 



As far as land and freshwater molluscs are concerned, 

 Lambay must be considered a poor field for research. The 

 western shores and low ground from Saltpan Bay, on the 

 north, to Carnoon Bay, on the south shore, are the habitats of 

 the great majority of the species found on the island. The 

 rest of Lambay, except for the margins of the few small 

 streams, is totally devoid of habitats suitable for most species 

 of mollusca. The best of the small streams is that running 

 into Freshwater Bay and the outlets of Raven's and Trinity 

 Wells, all of which are surrounded by marshy areas. The 

 sandy bluffs north of the harbour are the home of several 

 xerophiles, while the woods surrounding the castle and the 

 garden are the principal stronghold of the slugs. The almost 

 total absence of freshwater species in the following list will 

 be at once observed ; this is accounted for by the lack of 

 anything in the form of a lake or even a pond. The following 

 species, although not found by us on the island, might be 

 expected to occur : — Hyalinia cellaria, Agriolimax Icevis, Helix 

 pulchelldy Vertigo a?itivertigo, and V- substriata. 



List of Species. 



Vltrina pelluclda, Mull.— Dead shells only, near the castle, Scotch 



Point, and Heath Hill. 

 Hyalinia alllarla, Miller. — Rare, near the castle and at Scotch Point. 

 H. pura, Alder. — A few in the marsh surrounding Raven's Well 

 H. radlatula, Alder. — Several dead shells in the rejectamenta of 



Raven's Well. 

 H. nltldula, Drap.— Collected by Dr. R. F. Scharff during several 



visits to Lanibay 

 H. crystallina, Mull.— Common lii marsh at Raven's Well and at 



Scotch Point. 

 H. fulva, Mull.— One dead shell at Raven's Well. 

 Arlon ater, L. — The jet black form was noticed in swarms towards 



dusk in the central moorland parts of the island. The brown forms 



were in predominance near the coast. 

 A. subfuscus, Drap.— Rare at Raven's Rock, and also in the planta- 

 tion round the castle. 

 A. hortcnsls, Fer.— Found in abundance on the rocky talus at Calico 



Hole and in the plantation, all very dark in colour. 

 A. circumscrlptus, Johnst.- Common in the castle garden and 



plantation. 



