ACTINOPODA, HELIOZOA 409 



tion studied by Belaf (p. 164); Looper (1928) studied its food re- 

 actions. 



A. vesiculata Penard. Ectoplasm with saccate secondary vesicles, 

 extending out of body surface between axo podia; nucleus central, 

 with many endosomes; 25-30/1 in average diameter; fresh water. 



Genus Actinosphaerium Stein. Spherical; ectoplasm consists al- 

 most entirely of large vacuoles in one or several layers; endoplasm 

 with numerous small vacuoles; numerous nuclei; axial filaments end 

 in the inner zone of ectoplasm. 2 species. 



A. eichhorni Ehrenberg (Figs. 6; 190, c). Numerous nuclei scattered 

 in the periphery of endoplasm; 2 or more contractile vacuoles, large; 

 axial filaments arise from a narrow zone of dense cytoplasm at the 

 border line between endoplasm and ectoplasm; body large, diameter 

 200-300/i, sometimes up to 1 mm.; nuclei 12-20/z in diameter; among 

 vegetation in freshwater bodies. 



A. arachnoideum Penard. Ectoplasm irregularly vacuolated; no 

 distinct endoplasmic differentiation; nuclei smaller in number; pseu- 

 dopodia of 2 kinds; one straight, very long and the other filiform, 

 and anastomosing; 70-80/x in diameter; fresh water. 



Genus Camptonema Schaudinn. Spheroidal; axial filaments of 

 axopodia end in nuclei about 50 in number; vacuoles numerous and 

 small in size; salt water. 



C. nutans S. (Fig. 190, d). About ISOyu in diameter. 



Genus Oxnerella Dobell. Spherical; cytoplasm indistinctly dif- 

 ferentiated; eccentric nucleus with a large endosome; axial filaments 

 take their origin in the central granule; no contractile vacuole; 

 nuclear division typical mitosis (Fig. 58). 



0. maritima D. (Fig. 58). Small, 10-22/i in diameter; solitary, 

 floating or creeping; salt water. 



Family 3 Ciliophryidae Poche 



Genus Ciliophrys Cienkowski. Spherical with extremely fine 

 radiating filopodia, giving the appearance of a typical heliozoan, 

 with a single flagellum which is difficult to distinguish from the nu- 

 merous filopodia, but which becomes conspicuous when the pseudo- 

 podia are withdrawn; fresh or salt water. 



C. infusionum C. (Fig. 191, a). 25-30/x long; freshwater infusion. 



C. marina Caullery. About 10/x in diameter; salt water. 



Family 4 Lithocollidae Poche 



Genus LithocoUa Schulze. Spherical body; outer envelope with 

 usually one layer of sand-grains, diatoms, etc. ; nucleus eccentric. 



