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 
Arcelle, but rendered bright green from the presence 
of abundance of chlorophyl-corpuscles in the endo- 
plasm. Pseudopodia colourless, digitate. 
Fra. 24, Fic. 25, 
Fias. 24 and 25.—Arcella artocrea (face and side views), after Leidy. 
x 250. : 
Dimensions: Greatest breadth, 176 pw (Leidy). 
Bog above the lakes at Capel Curig, North Wales; 
Co. Donegal, Ireland (G. S. West). 
The species seems to be very rare, even in America. 
West (loc. cit.) found, in the locality above mentioned, 
a very large form, the diameter of the test (inclusive 
of the rim) measuring 300 w; that of the mouth 32 p; 
the height of the test being about 110. Specimens 
from County Donegal, Ireland, were not more than 
85 win diameter. Only empty tests were observed. 
‘The body of these was faceted, as in many of the more 
angular forms of A. valgaris. 
