HELEOPEEA PETEICOLA. 139 



Loch Ness {D. J. Scourfield), and Ben Ledi {W. Evans), 

 Scotland. Killough and Calary Bog, Co. AVicklow, 

 Ireland (/. MojpJcinson). 



The variation of H. petricola is remarkable, but 

 though one might be tempted to differentiate the 

 forms and say that certain of them represent distinct 

 varieties, yet the fact that they merge into one another 

 precludes such treatment. There is a small form very 

 abundant in North Wales (represented by the figs. 13 

 and 14 on Plate XXIX) which seems to preserve its 

 characters more than any other, but even this presents 

 no special feature — unless it be in the matter of size — 

 which "would justify its separation from the type. 

 Penard, in ' Faune Rhiz. Leman,' has some pertinent 

 remarks on the variability of the species, and he points 

 out a tendency (also noted by Scourfield in his paper 

 on the rhizopodous fauna of Spitzbergen*) on the 

 part of individuals to acquire a violet tint. 



Var. major, var. nov. (Plate XXIX, figs. 20 and 21.) 



Resembling the typical form of the species, but 

 generally larger, and with a colourless or lightish grey 

 test devoid of any purplish tint ; the mouth slightly 

 less convex, but narrowed, with the corners gracefully 

 rounded off ; the lateral margins from the crown down- 

 Avards nearly straight. The nucleus normally situated, 

 but obscured more or less with the granular and chloro- 

 phyllous contents of the plasma ; one or more clear 

 vesicles also present ; the pseudopodia numerous, thin, 

 aggregated about the mouth. 



Dimensions : Length 120-125 /a. 



In Sphagnum, and amongst aquatic mosses at 

 pond sides ; Dunham, Cheshire, and Padgate near 

 Warrington. 



* ' Proceedings of the Zoological Society of London/ June, 1897, p. 788. 



