FROM NEW YORK, NEW JERSEY, AND GEORGIA. 129 



Order AMCEBINA. 



The sj)ecies recorded belonging to this Order consist ahnost entirely o£ the 

 genus Amoeba : they are local in their occurrence, in some places plentiful, 

 in others scarce, but this may be in part due to the method of collection, 

 which was not directed particularly to insure their capture ; no very large 

 individuals were seen, and many of the small ones had the appearance of 

 being immature and their identity was doubtful. 



[Cockerell (12, 1911) records this genus as Amiba {vide Stiles & Hassall, 

 Bureau of Animal Industr., U.S. Dept. Agric, Bull. 79, 1905, p. 38).] 



Order CONCHULINA. 



Genus Arcella, Elirenberg. 

 Nine species and two varieties are recorded in this genus ; the limits of 

 some of the species are somewhat vague and may include forms which are 

 entitled to specific or varietal names. The life-histories of some of the forms 

 are required to clear up doubtful points. A general tendency for the 

 apertures to become crenulate was observed. 



Arcella angulosa, Perty. 



A. vulgaris var. angulosa, Leiclj, pi. 28. iigs. 8-13 (30). 



A. costata (Elirenb.), Penard (36). 



Not common, and sometimes closely approaching forms of A. mitrata. 

 Diameter 81-100 yu, ; aperture about -1- diameter. 



A. arenaria, Greef. 



A. microstoma, Pen. 

 A. aureola, Maggi. 



Recorded from Good Ground only : diameter about 80 [ji ; aperture 

 1 diameter. 



Distribution, Long Island, N.Y.; Canada (39) ; Colorado (35). 



A. ARTOCREA, Leidy. 

 (30) pi. 30. figs. 1-9. 



Often numerous : in one individual the pores around the aperture were 

 occupied by nodules or buttons 2'5 //- in diameter and projecting internally 

 1-75 /^ (PJ. 12. fig. 1). 



Diameter 120-230 fx ; aperture 23-47 fi ; height 50-63 fi. 



Two individuals from Augusta, Ga., had apertures 65 //, diameter. 



A. DENTATA, Elirenberg. 



A. stellar is, Perty. 



Leidy, pL 30. figs. 10-19 (30). 



This is a scarce species and is recorded only from Good Ground, where it 

 occurs in a small pond at the head of Smith's Creek, 



