HELIOZOA 23 



4. ACTiNOSPHiERiUM Stein. Like Actinophrys but with sharply 

 defined and vacuolated ectosarc: 1 species. 



A. eichhorni (Ehrenberg) (Fig. 18). Diameter up to 1 mm.: in 

 fresh water; common. 



Suborder 2. CHLAMYDOPHORIDA. 



Body spherical and with a soft gelatinous or felted covering in 

 which foreign bodies may be present: 5 genera. 



Heterophrys Archer. Body with a slight differentiation into 

 ectosarc and entosarc; pseudopodia radiating from all sides: 2 species; 

 in fresh and salt water. 



H. myriapoda Archer. Diameter .08 mm.; pseudopodia twice as 

 long as diameter of body; chlorophyll bodies often present: in fresh 

 and salt water. 



Suborder 3. CHALARATHORACIDA. 



Isolated silicious needles present which cover the outer surface: 8 

 genera. 



1. Raphidiophrys Archer. Body spherical, covered with silicious 

 needles lying tangentially ; ectosarc and entosarc not distinct ; pseudo- 

 podia with axial threads radiating from all sides ; often forming colonies 

 which have a common covering: 4 species; in fresh water. 



R. elegans Hertwig and Lesser. Diameter .04 mm.; often with 

 chlorophyll bodies: in fresh water. 



2. AcANTHOCYSTis Carter. Spherical animals in which the silicious 

 needles project radially; between them are the thread-like pseudopodia, 

 each with an axial thread; tangential needles may also be present: 10 

 species; in fresh water. 



A. chaetophora (Schrank). Diameter .1 mm.; needles of 2 forms, 

 a short and a long, both forked, and both with basal plates. 



Suborder 4. DESJ^fOTHORACIDA. 



Body enclosed in a silicious spherical shell containing numerous 

 round holes; a central nucleus; many contractile vacuoles and filiform 

 pseudopodia: 2 genera. 



Clathrulina Cienkowsky. Body spherical and fastened by a stalk 

 to some fixed object: the body does not fill the shell, which is absent in 

 the young individuals : 2 species ; in fresh water. 



C. elegans Cienk. (Fig. 19, p. 24). Diameter of shell .07 mm.; length 

 of stnlk up to .3 mm. : in pools. 



