112 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.3 



PLATE 17 



Figs. 1, 2. Final stages in the escape of the zygote. In Fig. 2 the 

 body has started to rotate on its long axis, and the 

 ciliuni is in motion. 



Fig. 3. Amoeboid changes of shape undergone by the zygote 

 during temporary periods of rest. 



Fig. 4. Zygote at rest. The body has become rounded and the 

 cilium condensed into a small droplet. 



Fig. 5. Mature oospore free in the water. 



Fig. 6. Germinated oospore. The full length of the hypha is 

 not shown. 



Fig. 7. Two oospores formed within the oogonium. Occur- 

 ring commonly under poor environmental conditions. 



Fig. 8. Unusually large oogonium containing six eggs. 



Fig. 9. Discharging zoosporangium. A mature zoospore with 

 the typical internal structure assumed during motility 

 is shown in the upper right figure. 



Fig. 10. Portion of a hyphal tip bearing an immature zoo- 

 sporangium and an empty oogonium beneath which 

 are several antheridia. 

 Figures inked in by Richard Higgins. 



