A , Euglena. viridis ; m, the so-called mouth ; , the nucleus ; e, the 

 stigma ; r, reservoir ; c.v., contractile vacuoles ; chr, chromatophors ; 

 am, pyrenoids with sheaths of pararriylum. B, another specimen, 

 showing change of shape and diagonal striation of the cuticle. 

 C and D, outlines to show various stages of contraction. E, a free 

 swimming specimen undergoing longitudinal division. F and G, 

 division of an encysted form. (AD, original ; E G, after Stein.) 



