4l8 MII.NE : CONTRIBUTIONS TOWARDS IRISH MOLLUSCA. 



dwelling-place, which was simply dry white sand without 

 vegetation. 



H. rotundata is another of the vanishing species ; plentiful in 

 the deposits, it is now restricted to Slievemore village, and 

 there is scarce ; whereas on the mainland it is still numer- 

 ous, as far as the limestone extends, being associated with 



H. rupestris, and beyond this living in large colonies by itself. 

 As to the two last species, I offer no opinion whether their 

 prosperity is decreasing or waning ; they are 



H. pygmaea which is found under stones on the walls of the 

 fields near the Colony, and 



H. pulchella, which is fairly plentiful on the warren. 



Bulimus acutus is, I think, a new comer; it is plentiful on 

 the warren by Lough Nambrack, but does not extend far, 

 though the whole neighbourhood looks suitable for it ; nor 

 does it occur in the deposits. 



Pupa umbiiicata is ubiquitous ; it is the only one of the 

 Helicidse which ventures on to the peat ; it is found all 

 along the shores of Clew Bay ; and in Achill it occurs from 

 the sea level at Annagh Bay and the Colony up to the 

 Signal Tower, 890 feet above the sea. The Achill examples 

 all look stunted ; some ftom Innishbiggle, on the contrary, 

 are high, but belong to var. edentula. 



At the Colony occur four species of Vertigo; three in 

 the dry ditch, where F. pusilhan, L. tnmcaUda, and S. 

 piitris are found, viz: 



V. anti vertigo, which is exceedingly numerous; 



V. substriata, which also extends up into the field, while 

 Anttvetiigo does not travel beyond the thick moss of the 

 ditch; and 



V. edentula. 



The fourth species prefers the walls of the gardens 

 and fields; this is 

 V. pygmaea, a snail common throughout Ireland. 



J.C, vi., Oct., :8gi. 



