Till] RADIOLAI.iA. g3 



or "vacuoles," which, rhythmically, become distended with 

 water, and are then obliterated by the contraction of the sur- 

 rounding protoplasm. But in the Actinophrya (or more 

 properly Actinosphcerium) J^ichornii (Fig. 4), the central 

 part of the protoplasm is distinguished from the rest by con- 

 taining a number of endoplasts. It thus leads to the AW/oA/- 

 ria (Polycistina of Ehrenberg), the simplest forms of which 



Pio. 4.-Actinosphvrlum Efchhornil (after Hertwis and Lesser, " Ueber Rhizopo- 



den," Schulze's Archiv, 1876). 

 I. The entire animal ; c, c, contractile vacuoles. 

 II. Part of the periphery much magnified; a, a, a, psendopodia with etiff axial enb- 



stance ; n. nuclei or endoplasts. 

 HI. A very yonng Actinosphoerium, with only two nuclei and two pseudopodia, 



much magnified. 



consist essentially of a myxopod provided with filamentous, 

 radiating, and often anastomosing, pseudopodia. The centre 

 of the body is occupied by a capsule filled with protoplasm ; 



