PLATE XV. 
Arcella vulgaris Ehrenb. (p. 118) Pond, Cheshire. 
x 300. Fig. 1—A young individual, in active 
movement, with transparent test. Figs. 2 and 3.— 
Empty tests of the same form. 
. A. discoides Ehrenb. (p.122) Pond, Cheshire. x 300. 
Figs 4 and 5.—Lateral and dorsal views of living 
individuals. Fig. 6—A young individual with 
imperfectly-formed test. 
. A, dentata Ehrenb. (p. 125) Dorsal and lateral 
views, showing character of test. x 3800. 
A. mitrata Leidy. (p. 124) Dorsal and lateral views, 
after Leidy. x about 300. 
A. vulgaris var. gibbosa (Penard) G.S. West. (p. 121) 
A small variety, with facetted test. Frequent in 
ponds. x 300, 
A, vulgaris var. angulosa (Perty) Leidy. (p. 121) In 
outline, after Leidy. x 250. 
A. vulgaris, Figs. 13 and 14.—Dorsal and lateral 
views of a young individual; the test transparent, 
with dilated base. Fig. 15.—A remarkably fine 
variety, with pitted test. Pond at Park Bridge, 
Lancashire. x 300. 
