LAND AND FRESH-WATER MOLLUSCA OF GREENOCK. 281 



find a variety of Helix nemoralis with, the shell 

 slightly smaller than nsual, semitransparent, and of 

 a greenish-yellow colour; but after the animal has 

 been killed the shell becomes opaque and of a more 

 decided yellow colour. This variety — the only one I 

 have noticed at that place — I do not find anywhere 

 else in the district. At the "Moat-hill," Cupar-Fife, 

 I got an almost black variety of the same species. 

 At that place most of the shells are of a blackish 

 colour; but nowhere else in the neighbourhood 

 did I find them so dark, though I have got 

 them of a somewhat similar colour on the Castle- 

 rock, Edinburgh. Again, at a place near Kenmore, 

 Perthshire, I gathered some s^Decimens of the same 

 species, of a yellow ground-colour, with dark brown 

 bands; but in adult specimens these bands became 

 broken up and diffused over the ground-colour just 

 before reaching the lip, thus producing a rather 

 pleasing effect. This peculiar band-dispersion .was 

 not observed in specimens gathered from any other 

 place in that locality. Accordingly, when variations, 

 though only in colour, are met with, and appear to 

 be strictly local, as in these examples, the reason for 

 such restriction forms a subject of enquiry at once 

 interesting and important. 



It will be seen from the List, which has been 

 prepared for me by my son Andrew, that the 

 aquatic species are but poorly represented in our 

 district. With perhaps one or two exceptions, all 

 those recorded are comparatively common, the reason 

 being that there are few places suitable for the 

 propagation of aquatic molluscs. One of the excep- 

 tions I have mentioned is Pisidium nitidum. I find 

 this siDecies — along with other two interesting things, 

 viz. : Candona eiiplectella (an ostracode) and Utricu- 

 laria Tninor (a bladderwort) — in some pools by the 

 side of the road leading from Port-Glasgow to 

 Kilmalcolm. These pools occur in a natural hollow 

 through which the road passes, and are probably 

 .all that remain of what was once a considerable 



