152 THE AMERICAN NATURALIST. | (Vor. XXXIX. 
Nebela flabellulum Leidy. 
Test largely composed of circular disks much as in the pre- 
ceding. 
Sise.— Length, 63-90 a; breadth, 75-100 p; aperture, 
18-20 p. 
Localities. — Lake of the Clouds (B. S. N. H., no. 4319); 
Scribner's Brook, Wakefield (B. S. N. H., no. 4786); Mt. 
Moosilauke (Henderson Coll., no. 74). 
Arcella vulgaris Ehrenberg. 
Test a yellowish or brown chitinoid membrane, with minutely 
hexagonal cancellation. The common form of the upper surface 
is an evenly rounded dome, but two or three individuals showed 
top and sides depressed into bluntly angular facets. 
Size. — Length, 42 p; breadth, 23-54 m; aperture, 11-15 p. 
Localities. — Mt. Munroe (Cushman Coll, no. 194) ; Saco 
Lake (B. S. N. H., nos. 4235, 4323). 
Arcella discoides Ehrenberg. 
Test of same material as in the preceding, in form more flat- 
tened. 
Size. — Length, 29-44 p; breadth, 77-108 p; aperture, 
19-42 p. 
Locality. — North Woodstock (Cushman Coll., nos. 176, 179, 
198, Henderson Coll., nos. 54, 64). 
Arcella mitrata Leidy. 
Test of same material as in the preceding. In form, viewed 
either from above or from below, with the circular outline broken 
by the salient angles of the strongly marked facets. In side 
view, the shell is crown-shaped. 
Size. — Length, 63-135 p;. breadth, 67-155 yw; aperture, 
34-63 p. 
Localities. — Lake of the Clouds 
(B. S. N. H., no. 4319); 
Pudding Pond, N v 
orth Conway (Henderson Coll., no. 79). 
