34 



BIOLOGY OF THE PROTOZOA 



Radiolaria, of bars, hexagons, rings, fenestrated capsules, etc. 

 (Fig. 12). 



Freely moving types are usually monaxonic. The type form of a 

 freely moving flagellate or holotrichous ciliate is ellipsoidal, the cell 

 being drawn out with its main axis extending in the direction of 

 movement. Attached forms are usually polyaxonic or radially sym- 

 metrical, the variations in form depending upon the nature of the 





B 



Fig. 13. — Diphasic rhizopods. A, B, C, heliozoa-like and flagellated stages of 

 Dimorpha mutans, (After Blochman.) D, E, F, Dimastigamoeba gruberi, ameboid 

 and flagellated stages; E, origin of blepharoplast (bl) from endosome; r, rhizoplast. 

 (After C. W. Wilson.) 



attaching portion. Some for example are attached by the proto- 

 plasm of the posterior end of a cylindrical body (e. g., Cothurnia, 

 Vaginicolla, etc.); others by the more or less stalk-like attenuated 

 end of the body (e. g., Scyphidia, Podophrya, etc.); and others by 

 chitinous stalks of variable length (Vorticella species) which may be 

 more or less branched (Poteriodendron, Epistylis, Carchesium, Zooth- 

 amnium, etc.). In the same individual the form may change with 



