230 FRESH-WATER BIOLOGY 



118 (117) Margin of neck not dentate. Spkenoderia lenta Schlumberger 1845. 



Shell ovoid or rounded with large, round imbricating plates. The aper- 



L^^^^ ture consists of a narrow, elongated opening, extending between two lateral 



Ji»,....JR<j points opposite each other. Pseudopodia are numerous and very long. 



Habitat sphagnum. Length from 35 to 50 li. Leidy describes a species 



under the name 5. macrolepis, differing from other species by the angular 



plates composing the shell. Habitat sphagnum. Length 24 to 39 a. 



Fig. 331. Spkenoderia lenta. ' cu, contractile vacuole. X 300. (After Leidy.) 



119(116) Shell compressed, without a neck 120 



120 (137) Aperture terminal 121 



121 (136) Margin of aperture dentate 122 



122(125) Plates elongate-eUiptical; margin of aperture finely dentate. 



Assulina Ehrenberg . . 123 



123 (124) Large size, rounded. . . . Assulina seminulum Ehrenberg 1848. 



i'^-^S'i^l^^ Adult forms of this species are chocolate brown in color. Con- 



tractile vacuole single. Nucleus very large, elliptical. Pseudopodia 

 seldom observed. Common in sphagnous swamps. Length 60 to 

 88 M. 



Fig. 332 Assulina seminulum, cv, contractile vacuole. X 290. 

 (After Leidy.) 



[24 (123) Small size, oval Assulina minor Penard 1890. 



This species is also brown in color but clearer than the preceding one and 

 the aperture is more regularly crenulate. The hexagonal design formed by the 

 imbricating plates is very symmetrical. Found among mosses. Length 35 ij.. 



Fig. 333. Assulina minor. X 300. (After Penard.) 



Plates round or oval; margin of aperture with prominent denticles. 

 Spines often developed. . . . Euglypha Dujardin . . 126 



X26 (133) Aperture circular 127 



127 (130) Spines at apex only 128 



X28 (129) Spines, one or two Euglypha mucronata Leidy 1878. 



The shell not compressed; plates imbricating, arranged in 

 longitudinal, alternating rows. The fundus tapers to a point 

 which is provided with one or two spines. Found in sphagnous 

 swamps. Reported from North America only. Length 108 tc 

 140 c- 



Fig. 334. Euglypha mucronata. X 163. (After Leidy.) 



129 (128) Spines in a tuft Euglypha cristata Leidy 1874, 



Shell elongated, very little compressed if any, with plates arranged 

 as in preceding species. Pseudopodia rarely extended. Habitat 

 sphagnous swamps. Length 33 to 84 11. 



Fig. 33S. Euglypha cristata. X 42S. (After Leidy.) 



130 (127) Spines not at apex only i^i 



