128 



BRITISH FRESHWATER RHIZOPODA. 



angular, and entire, the central portion of the base 

 everted in the usual concavely infundibuliform 

 manner ; the mouth circular, entire,- surrounded with 

 a circle of minute tubercles. The plasma-body having 

 the same general form and relationships as in other 

 Arcellse, but rendered bright green from the presence 

 of abundance of chlorophyl-corpuscles in the endo- 

 plasm. Pseudopodia colourless, digitate. 



FIG. 24. 



FIG. 25. 



FIGS. 24 and 25. Arcella artocrea (face and side views), after Leidy. 



x 250. 



Dimensions: Greatest breadth, 176 /A (Leidy). 



Bog above the lakes at Capel Curig, North Wales ; 

 Co. Donegal, Ireland (<?. 8. West). 



The species seems to be very rare, even in America. 

 AVest (loc. tit.) found, in the locality above mentioned, 

 a very large form, the diameter of the test (inclusive 

 of the rim) measuring 300 /A; that of the mouth 32 /x ; 

 the height of the test being about 110 /a. Specimens 

 from County Donegal, Ireland, w r ere not more than 

 85 ju, in diameter. Only empty tests were observed. 

 The body of these was faceted, as in many of the more 

 angular forms of A. vulgaris. 



