Mollnsks. 7207 



at low water ; the Allans, Cumbrae and Lamlash Bay ; also taken 

 with the dredge on fronds of Lanninariae. 



T. pusillus. Common in Lamlash Bay, more particularly in that 

 part known as " Landsborough's Bay." 



Adeorbis subcarinatus [Trochus suhcarinatus). Among shell-sand 

 from Lamlash Bay. 



Fam. VII. lanihinidm. 



lanthina communis. Is mentioned by Mr. Smith as having been 

 taken at Loch Ryan. Loch Ryan is a little to the south of 

 the district which this paper includes, but as the lanthina is an 

 oceanic shell there is no reason why a " west-sou'-wester " may not 

 waft it from the Atlantic to the Ayrshire coast. 



Fam. VIII. Littorinidce. 



*Littorina neritoides {Littorina petrcea. Turbo neritoides). Local, 

 but not uncommon, and may be met with in some abundance on the 

 rocks of the outer Allans, Cumbrae. 

 *L. rudis {Littorina vulgaris^ Turbo rudis and T. rugosus). 

 Common. 



L. patula. Local. On the rocks at Callums Hole, Bute, and at 

 the Corriegills, Arran. 



L. tenebrosa. In little pools in the salt marsh at Brodick. 



L. saxatilis {Littorina neglecta). Plentiful in company with L. 

 "neritoides at Allans, Cumbrae ; also in rock pools at Clachland 

 Point, Arran. 

 *L. littorea {Turbo littoreus). Common. 

 *L. littoralis. Common. 



Lacuna pallidula {Natica pallidula). Rock pools, Cumbrae, not 

 common ; Lamlash, Ayr, Smith. 



L. puteolus. Frequent in a large rock pool at the outer Allans, 

 Cumbrae. The strata of the Allans dip towards the sea. The 

 sea has worn away the softer material between two upturaed out- 

 cropping layers that raise themselves out of the sea, presenting their 

 smooth, sloping, and steep-inclined surfaces to the sea, and their 

 broken and rugged summits to the land. The channel thus worn 

 away between the two strata forms a large rock pool, the bottom of 

 which is never disturbed even in the heaviest seas. The water finds 

 its way in and out of this rock pool by narrow channels passing^ 

 between the loose piled-up stones which close the entrance at either 



