264 ZYGNEMATACEAE 



PLATE X 



Hallasia and Zygogonium 



Figs. 1-9. — Hallasia reticulata, vegetative cells and aplanospores. In 

 some of the aplanospores secondary spores are formed which are released by 

 the separation of the two valves of the aplanospore wall. In Fig. 9 a several- 

 celled sporeling is depicted. After Hallas. Figs. 10-16. — Zygogonium 

 ericetorum, vegetative cells, akinetes, aplanospores, and zygospores in various 

 stages of development. All but Fig. 14 are from Longwood, Florida. In 

 Fig. 14 are filaments with an aplanospore and three encysted and united 

 gametes, from Kwangtung, China. Figs. 17-19. — Z. mirabile, zygosporangia 

 and vegetative cells from Portuguese West Africa. After G. S. West. 



