564 Scientific Proceedings^ Royal Dublin Society. 



PLATE XLIV. 

 Figs. 

 11-21. PJijitophtJiora erythroseptica. 



11. An antheridium into wliicb the oogonial incept has penetrated. After 



treatment with weak caustic soda and staining with Loeffler's methylene 

 blue. — oh = oogonial hypha, ah = antheridial hypha, an = antheridium, 

 oi = oogonial incept, x 625. 



12. Sexual organs drawn about ten minutes after the developing oogonium had 



burst out through the top of the antheridium. The antheridium an is sessile 

 on the now empty antheridial hypha ah, the point of origin being at the 

 back, and not shown in the drawing. The oogonial incept was sessile on 

 the oogonial hypha oh, which is considerably swollen at the point of origin 

 of the former. The funnel-shaped base of the developing oogonium og is 

 only very faintly seen within the antheridium, the broken wall of which at 

 the point of exit is somewhat jagged in outline. At this stage there was 

 rather rapid movement of protoplasm from the oogonial hypha into the 

 developing oogonium. Living material, x 626. 



13. The same organs as in fig. 12 after the lapse of a period of thirty minutes. 



The developing oogonium has increased considerably in size, x 625. 



14. The same after a further period of 2 hours 20 minutes. The broken wall of 



the antheridium is no longer jagged, but the " beaded" edge is becoming 

 defined, x 625. 



15. The same after a further period of 2 hours 10 minutes. The oogonium is 



rapidly attaining its full size, and the contents of the hypha h are diminish- 

 ing in quantity, being drawn upon to fill the oogonium. The funnel- 

 shaped base of the developing oogonium is rather more distinct in this 

 figure than in figs. 12, 13, and 14. x 625. 



16. The same, 17 hours 20 minutes later than fig. 12. The oogonium has attained 



its full size; the oogonial hypha has lost most of its contents. Protoplasmic 

 streaming into the oogonium had ceased some time before this. The 

 contents of the antheridium have largely disappeared, revealing clearly the 

 funnel-shaped base of the oogonium within it ; the hypha h has lost its 

 contents and become reduced in size. ' x 625. 



17. Another set of the sexual organs, oosphere stage. Part of the contents of 



the upper portion of the oogonium have become rounded off, in preparation 



for the development of the oospore, the remainder forms trabecular 



structures which subsequently disappear or it exists as isolated granules 



"ound the periphery. A " plug " in the funnel-shaped base of the 



^nium is present having its upper and lower edges concave, and the 



ne more distinct than the lower. The thickness of the oogonium 



■^ewhat exaggerated in this figure. Living material, x 425 



