Nichols — A List of the Marine MoUusca of Ireland. 521 



Littorina rudis (Maton). 

 i., ii., iii., iv., v., vi. 

 Very common everywhere. 



Var. saxatilis, Johnston. N., E., and W. of Ireland (Thompson, 

 '44) : Portmarnock (Adams, '78) : Eoundstone (Alcock, '65). 

 Yar. j'uffosa, Montagu. " Common on all quarters of the rocky 

 coasts" (Thompson, '56) : Greystones (Adams, '78) : Valentia 

 (Cockerell, '87). Yar. pafula, J eEvejs. Belfast Lough, living, 

 common (Hyndman, '58) : Dublin Bay (A. Macalister, f. 

 Adams, '78). Yar. fflohosa,JeSrejs. Dublin Bay (Branscombe, 

 f. Clark, in Jeffreys, '65). Var. teneirosa, Montagu, Generally 

 distributed on muddy flats in estuaries, &c. 

 Distribution. — Spitzbergen. Iceland. Pinmark to Azores. ? Medi- 

 terranean. Greenland. 'N. E. America. I^. W. America. Mexico 

 (Jeffreys). 



Littorina littorea (Linne). 

 i., ii., iii., iv., v., vi. 

 Common all round the coast. 

 Var. turrita, Jeffreys. Belfast Lough (Stewart, f. Praeger, '89 ; 



Marshall, '98). 

 Distribution. — "White Sea to Portugal. ? Mediterranean. iN". E. 

 America. Mexico (Jeffreys). 



Lacuna crassior (Montagu). 



i., ii., iii., . v., vi. 

 i. Common. 

 ii. Dublin Bay (Turton, f. Brown, '18; Leach, '52 ; Kinahan, '61 ; 



"Warren Coll. in Dublin Mus.). 

 iii. "Woodstown, co. "Waterford (Dublin Mus., coll. by Mrs. 

 Tatlow) : " Porcupine" Exp., 1869, 74 fms. (Jeffreys, '83). 

 V, Birterbuy Bay (Earran, f. Thompson, '56) : Achill I. (Mrs. 



Tatlow & Praeger, '98). 

 vi. Iniskeen, co. Donegal, abundant (Mrs. Tatlow, '99). 



Distribution. — Spitzbergen. "White Sea. Eussian Lapland. British 

 Isles. N. W. France. Greenland, IST. E. America. N. Pacific. 



Lacuna divaricata (Fabricius). 

 i., ii., iii., iv., v., vi. 

 Abundant round the coast in the littoral and laminarian zones. 

 Var. canalis, Montagu, and var. quadrifasciata^ Montagu. Ap- 

 parently generally distributed. 

 Listribution. — Arctic seas to Algiers, New Jersey, and N, Japan. 



