AMCEBA. 



less black by transmitted light, pale yellowish by re- 

 flected light. Pseudopodia digitate and blunt, sometimes 

 tapering and pointed. Nucleus usually single, discoidal, 

 posterior; contractile vesicle usually large and single, 

 generally behind the nucleus. The special charac- 

 teristic of this species is the digitate and blunt pseudo- 

 pods. 



A. verrucosa. Mature animal, rather sluggish, irregu- 

 larly oval, round or quadrately rounded form, with wart- 

 like expansions, and a more or less wrinkled surface, as 

 though invested with a membrane. Pseudopodia short, 

 broad and blunt. Endosarc pale, granular, with few or no 

 coarse granules. Ectosarc copious and hyaline. Con- 

 tractile vesicle large. Nucleus usually distinct. Size 

 ranging from 80^ by -72// to 180/z by 160^. Very 

 common. 



Young animal actively moving, body oval or pyriform, 

 usually moving with the broader pole in advance ; sur- 

 face comparatively smooth, but generally marked with 

 four longitudinal lines or folds (Ammba quadrilineata, 

 Carter) ; contractile vesicle posterior. Nucleus in 

 front of the vesicle. Size from 40// by 20^ to 120// 

 by 90jw. 



A. 'Padiosa. SYN. : A. radiosa, Ehr., brachiola, Duj., ramosa, 

 Duj. 



Comparatively small, colorless and inactive. When 

 floating free in the water stellate, with a spheroidal or oval 

 central mass with from two to three, or a dozen or more, 

 radiating pseudopods of variable length and form, mostly 

 conical and acute or attenuated and thread-like, sim- 

 ple, straight, apparently rigid, curved or flexuose. On 



