No. 459.] WHITE MOUNTAIN RHIZOPODS. 153 
Centropyxis aculeata (Ehrenberg).: 
Test of yellow or brown chitin as in Arcella. In some of the 
specimens examined, quartz grains were incorporated in the 
membrane. The form is always characteristic: mouth and 
fundus eccentric in opposite directions. The typical form has 
several spines crowning the fundus. 
Szze.— Greater diameter, 89-153 »; shorter diameter, 66— 
93 », aperture, 19—57 u. 
Localities — North Woodstock (Henderson Coll., nos. 52, 60, 
61); Squam Lake (Cushman Coll, no. 197); Pudding Pond, 
North Conway (Henderson Coll., no. 70) ; Intervale (Henderson 
Coll., nos. 66, 69) ; Gilmore Pond near Profile House (B.'S. N. 
H., no. 4314) ; Claremont (B. S. N. H., no. 4662). 
Centropyxis aculeata var. ecornis (Ehrenberg). 
As the name implies, the fundus is not crowned with spines. 
One specimen examined showed the Arcella-like cancellation of 
the shell noted by Leidy (p 183). 
Size.— Average length, 48 »; longer diameter, 48-144 u; 
aperture, I2—4I y. 
Localities — North Woodstock (Cushman Coll., no. 176, Hen- 
derson Coll., nos. 53, 62) ; Mt. Munroe (Cushman Coll., nos. 194, 
196); Profile Lake (B. S. N. H., no. 4313) ; Franconia (B. 5. 
N. H, no. 4307) ; Saco Lake (B. S. N. H., nos. 4325, 4324). 
Cyphoderia ampulla (Ehrenberg). 
The test in all specimens examined was of similar structure, 
and varied comparatively little in size. It isa delicate chitinoid 
membrane, colorless or faintly yellow, showing. minute hexagonal 
cancellation ; rim of oval aperture finely beaded. 
Size— Length, 104-143 4; extreme breadth, 42-50 »; aper- 
ture, 14-18 p. 
Localities.— North Woodstock (Cushman Coll., no. 189, Hen- 
derson Coll, nos. sr, 52, 63); Squam Lake (Cushman Coll., 
no. 198); Lake of the Clouds (B. S. N. H., no. 3719; Profile 
