312 PROTOZOOLOGY 



and certain bacteria; Hewitt obtained it from agar cultures of a 

 sample soil taken from among the roots of white clover; co-exist- 

 ing with yeast-like fungi, Flavohacterium trifolium and Rhizohium 

 sp. ; 12-30/i in diameter; cyst membrane without pore; some cysts 

 viable at 37°C. for 6 days. 



Genus Sappinia Dangeard. With two closely associated nuclei. 



S. diploidea (Hartmann et Nagler). Coprozoic in the faeces of 

 different animals; pseudopodia short, broad, and few; highly 

 vacuolated endoplasm with 2 nuclei, food vacuoles, and a con- 

 tractile vacuole; surface sometimes wrinkled; the nuclei divide 

 simultaneously; during encystment, two individuals come to- 

 gether and secrete a common cyst wall; 2 nuclei fuse so that each 

 individual possesses a single nucleus; finally cytoplasmic masses 

 unite into one; each nucleus gives off reduction bodies (?) which 

 degenerate; 2 nuclei now come in contact without fusion, thus 

 producing a binucleate cyst (Hartmann and Nagler). 



Family 3 Endamoebidae Calkins 



Exclusively endoparasitic amoebae; the vegetative form is rela- 

 tively small and occurs mostly in the alimentary canal of the 

 host; contractile vacuoles absent, except in Hydramoeba; multi- 

 plication by binary fission; encystment common. The generic dif- 

 ferentiation is based upon morphological characteristics of the 

 nucleus. Summary No. 99 of 'Opinions Rendered' by the Inter- 

 national Commission of Zoological Nomenclature (1928) holds 

 that Entamoeba is a synonym of Endamoeba; in the present 

 work, however, Endamoeba and Entamoeba are separated, since 

 the two groups of species placed under them possess different nu- 

 clear characteristics and since it is not advisable to establish an- 

 other generic name in place of Entamoeba which has been so fre- 

 quently and widely used throughout the world. 



Genus Endamoeba Leidy. Nucleus spheroidal to ovoid; mem- 

 brane thick; in life, filled with numerous granules of uniform di- 

 mensions along its peripheral region; upon fixation, a fine chro- 

 matic network becomes noticeable in their stead; central portion 

 coarsely reticulated; with several endosomes between the two 

 zones; in some, cytoplasm becomes prominently striated during 

 locomotion; in the intestine of invertebrates. 



E. hlattae (Biitschh) (Figs. 49; 143). In the colon of cock- 

 roaches; 10-150m in diameter; rounded individuals with broad 



