THE RADIOLARIA. 83 



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

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

 rounding protoplasm. But in the Actinophrys (or more 

 properly Actinosphcerium) Eichornii (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 Badiola- 

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



Fig. i.—Actinosf)h(emim Eichhornii (after Hertwig 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, pseudopodia with stiff axial sub- 

 stance ; n, nuclei or endoplasts. 



m.— A very young Actinosphcerium, 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 ; 



