224 w - M - SMALL WOOD. 



of these observations. The conditions certainly exist as drawn 

 but more drawings could be made easily showing different rela- 

 tions of the chromatin masses and vesicles. The eggs just after 

 deposition do not show these chromatin changes. After a time 

 the chromatin that remains in the male and female pro-nuclei 

 increases in amount and takes a deeper stain until the chromatin 

 appears like that shown in Figs. 16, PL IV., and 19, PI. Ill- 

 Hargitt in Fig. 48 has two similar vesicles. 



The vesicles last but a short time and usually are indistinguish- 

 able by the time that segmentation begins. But when such condi- 

 tions as shown in Fig. 16 exist in the presence of a small vesicle 

 containing chromatin near the female pro-nucleus and a second one 

 between the two pro-nuclei, these remain longer in the egg. 

 What their influence on subsequent development is, some light 

 may be gained by a study of Fig. 49 (Hargitt). In this drawing 

 there is a clearly defined mitotic figure with faint chromosomes ;. 

 and a short distance away, three asters and their connecting fibers 

 are around several vesicles. This Fig. 49 seems to be a later 

 stage in the transformation of some of these vesicles containing" 

 chromatin and indicates a pseudo-segmentation in that it is not 

 preceded by the fusion of the male and female pro-nuclei. It 

 hardly seems as if such conditions played an important part in the 

 future segmentation. 



FERTILIZATION IN THE EGG OF Pennaria. 



The spermatazoa penetrates the egg of Pennaria frequently 

 before deposition, but the penetration is usual after the egg is laid. 

 The false membrane may contain a large number of sperm heads 

 that were unable to gain admission into the egg. The sperm 

 head immediately after penetration becomes transformed into a 

 vesiculate body, the male pro-nucleus. No definite place of en- 

 trance, nor path through the cytoplasm, nor the presence of asters 

 could be determined. It remains smaller than the female pro- 

 nucleus and is surrounded by fine cytoplasmic granules. Figs. 

 15, PI. IV., 16, PI. III., and 18, PI. IV., give a good idea of the 

 male pro-nucleus. 



Figs. 17 and 19 show the approach of the pro-nuclei. The 

 fine cytoplasmic granules surrounding the two bodies have united 



