70 
HALLY JOLIVETTE SAX 
After considerable increase in size there is laid down a thick black 
wall around the upper portion of the spore which is ovoid in shape. 
The lower tail portion remains hyaline. It is separated from the 
larger portion by the thick black wall. The cytoplasm in the upper 
portion stains darkly, while that in the tail portion stains lightly. 
Figure 21 shows four spores from an ascus after the spore walls are 
thickened. The spores appear to be mature. The tail is entirely 
separated from the rest of the spore by a heavy wall. The nucleus 
occupies the central portion of the spore. The cytoplasm contains 
some large vacuoles. The tails are hyaline and extremely incon- 
spicuous in comparison with the heavy black spore walls. The cyto- 
plasm stains very lightly. Often near the distal end of the tail in a 
hyaline spot are found some dense red staining granules. The epi- 
plasm, though comparatively inconspicuous at this stage, is still 
present, and the plasma membrane of the ascus is intact. 
Discussion 
The abundance of well-fixed material of Philocopra coeruleotecta 
has made possible a detailed study of the processes in the development 
of the ascus and spore formation. It has proven especially favorable 
because of the variety of stages found in a single pyrenocarp. 
The nucleo-cytoplasmic relation shows considerable variation. 
The very young ascus containing the primary nucleus is not at all 
striking in this respect. The nucleus and cytoplasm do not exhibit 
any unusual proportion in respect to each other. Immediately fol- 
lowing this stage there is a rapid growth in the size of the ascus. The 
cytoplasm is slightly more vacuolate and has greatly increased in 
volume. The primary nucleus shows no signs of division for a con- 
siderable period. The cytoplasm actually doubles in volume several 
times while the primary nucleus remains in a resting condition. That 
part in the immediate neighborhood of the nucleus, however, shows 
no marked change. Then with further increase in the size of the 
ascus the primary nucleus divides. A period of successive divisions 
of the nuclei follows. The divisions follow one another with great 
rapidity, filling up the central peripheral portion of the ascus. Whether 
or not there is any relation between this series of rapid successive 
divisions and the great volume of cytoplasm is a question of con- 
siderable interest. If there is a definite relation between the volume 
of the nucleus and that of the cytoplasm, the quick successive divisions 
