I04 EXPLANATION OF FIGURES IN PLATES. 



PlAXe VII.— PhYI,I,ACTINIA CORYtBA, EXCEPT WHERE OTHERWISE INDICATED. 



Fig. 69. — Brysiphe cichoracearum. Dispirem stages ; third division ; polar asters 

 strongly developed. 



Fig. 70. — Beaked nucleus and aster in early stage of spore formation ; two super- 

 numerary nuclei at opposite end of ascus and lying with their central bodies on 

 the plasma-membrane of the ascus. 



Fig. 71. — ^Beaked nucleus and aster, opposite which the plasma-membrane is 

 drawn in forming an oval depression. 



Fig. 72. — Beaked nucleus with aster strongly developed; central body broader 

 than end of beak. 



Fig. 73. — Brysiphe cichoracearum. Metamorphosis of the polar aster to form 

 the plasma-membrane of the spore ; early stage in folding over of the rays ; two 

 supernumerary nuclei present; transverse section of part of membrane of third 

 spore shown in lower part of figure. 



Fig. 74. — B. cichoracearum; the rays have formed broad, bell-shaped membranes 

 about the nuclei; beak of nucleus lying to the right is cut off and appears in the 

 next section. 



Fig. 75. — B. cichoracearum; plasma-membrane of spore almost complete. 



Fig. 76.— Spore completely inclosed; beak of nucleus still attached to plasma- 

 membrane ; astral rays have disappeared entirely. 



Fig. 77. — ^Stage in drawing in of nuclear beak; central body conspicuous at the 

 tip of beak. 



Fig. 78. — ^Later stage, same process. 



Fig. 79. — Ascus with two spores; »ucleus in resting condition; chromatin con- 

 spicuously oriented on central body. 



Fig. 80. — B. communis; late stage in spore formation ; central body and system 

 of astral rays divided ; beak scarcely visible. 



Fig. 81. — B. communis; ascus with view of stage in spore formation looking 

 somewhat obliquely down upon the end of the spore; two supernumerary nuclei 

 in opposite end of ascus. 



