FLOATING PLANTS 



123 



Fig. 40. — Halosph^era. (From Murray's " Introduction to 

 the Study of Seaweeds," by permission of Messrs. 

 Macmillan.) 



In the sphere on the left the protoplasm has gathered round the 

 nuclei lining the wall ; that on the right has shed the outer 

 membrane, and the daughter cells have separated from the 

 wall ; below are four stages in the development of the zoospores. 



Fig. 4 i . 

 Peridinium. (After Cleve.) 



Fig. 42. 



Trichodesmium ("Blake"). 



