PLATE XL VI I 



Rheosporangium aphanidermatus: 



Fig. I. — Fertilized egg showing the two functional nuclei nearing juxtaposition. 

 X 2,000. 



Fig. 2. — Fertilization taking place before the central vacuole of the egg has entirely 

 disappeared. Disintegration of supernumerary nuclei well advanced. X2,ooo. 



Fig. 3. — Maturing oospore showing the large central food body and the fused nucleus 

 with two polar nucleoli. Xz.ooo. 



Fig. 4. — Oospore after the second nuclear division. X2,ooo. 



Fig. 5. — Fertilization: Cytoplasm and functional nucleus passing from antlieridium 

 to oosphere . X 2 , 000. 



Fig. 6. — Fertilization occurring before degeneration of the supernumerary nuclei. 

 Mitochondria shown passing into the oosphere with the nucleus. X2,ooo. 



Fig. 7. — First division of the fused nucleus in the oospore. The central food body, 

 which lies immediately beneath the nucleus, is not shown. X2,ooo. 

 92315— ° 15 2 



