62 THE SCOTTISH NATURALIST 



The lists of Rhizopoda here given, together with those of 

 J. M. Brown {Ann. Scot. Nat. Hist., October 191 1), enable a 

 general idea to be obtained of the distribution of the 

 Rhizopoda over the western portions of Scotland and the 

 adjoining islands ; these lists are very similar, showing a 

 general and fairly uniform distribution of species over the 

 whole area, wherever suitable habitats are to be found. A 

 few of the rarer may be restricted to certain areas, but these 

 areas are, as far as can be judged from existing records, 

 scattered over the British Isles. There is no evidence of 

 any group of species being peculiar to the Atlantic sea- 

 board. 



In the islands individuals of the species recorded were 

 generally numerous and often above the usual size. 



Arcella artocrea, Leidy. 

 Found only from Lewis. Not common in Great Britain, but 

 plentiful in the United States. 



Arcella hemispherica, Perty. 

 Generally distributed over Great Britain ; it is classed by Cash 

 and Hopkinson (3) as a form of A. vulgaris. It is recorded from 

 Loch Ness (Penard). 



Assulina seminulum, Leidy. 

 This species was found in large, fine specimens. At Dumfries 

 the size varied from 77-100 /x in length; in the Shetlands 100/x long 

 was an average size ; in the Hebrides it was less common. 



Var. scandinavica, Penard. 

 In the Shetlands this variety was plentiful, generally colourless 

 and transparent, with regularly arranged oval scales ; the size varied 

 from 100-120^ long (6, 10). 



Bullinula i/niica, Penard. 

 From Dumfries measuring about 190 by 160/x with an aperture 

 65 by 10 fx. This is larger than the average size of British speci- 

 mens (9, to). 



Campascus minutus, Penard. 



Only one individual was found, from N. Uist, Hebrides ; length, 

 57/x; breadth, 36 /x; thickness, 25 /x; aperture, 12 /x; collar, 16 fx. 

 It has only been recorded previously from Loch Ness and the Swiss 

 Lakes (Penard) (7). 



