24 THE SCOTTISH NATURALIST 



Helicella itala) were found on both lona and Innis Kenneth. 

 Twelve species were obtained only on Ulva, but it is probable 

 that most, if not all, occur also on the other islands. One 

 species {Pisidium nitidnm) was found only on the Ross of 



Mull. 



Notes on Species found. 



Liviax arhoruin. — Not uncommon in the woods of Ulva, both on 

 the ground and on pine-trunks. 



Agriolimax agrestis. — Common under stones on all the islands, 

 chiefly in the colour-forms pallida and reticulata. 



Arion ater. — By far the most abundant land-mollusc on Ulva, 

 not quite so common on the other islands. Only the black form 

 was observed in the bogs, but the form castanea was found in a 

 wood, and albolateralis under a stone in the open. 



Arion subfuscus. — Not so common on Ulva as round Callander, 

 Perthshire, and as a rule paler in colour. Under stones. 



Arion hortensis. — Common under stones on Ulva. 



Arion intermedins ( = niinimiis). Scarce, under stones. 



Vitrina pellucida. — In woods of Ulva, scarce. The few 

 specimens collected in August were immature, the last whorl of 

 the shell being not more than half-formed. 



Hyalinia cellaria. — With P. rotimdatus the commonest snail on 

 all the islands, under stones. All our specimens are small, and 

 many, especially on Innis Kenneth, belong to or approach the form 

 complanata. 



Hyalinia alliaria. — Much less common than H. cellaria. 



Hyalinia crystallina. — Fairly common on Ulva. 



Hyalinia radiatula. Scarce. 



Zonitoides excavatus. — Not very common. 



Zonitoides ?iitidus. — Not uncommon at the edge of mountain 

 streams, in which the dead shells were often found. A living 

 individual was taken among grass-roots in about lo inches of 

 water. 



Pyramidula rotundata. — Very common under stones on all the 

 islands. 



Hygromia fusca. — Single immature specimens were taken under 

 stones on Ulva and Eorsa. 



Helix aspersa. — Abundant on walls and ruins and under stones 

 on lona and Innis Kenneth. All the specimens are small (not 

 more than 30 x 34 mm., whereas a specimen from the coast of 

 Algeria is 47x44 mm.), but very little smaller than shells from 

 Edinburgh and the Bass Rock. Those from lona are darkly 



