32 RALPH E. WAGER. 



Explanation of Plate I. 



Fig. I. Longitudinal section through a portion of the germinal area. The charac^ 

 ter of the cells is well shown, as also the metaplasmic bodies frequently occurring in 

 these cells. The double character of the nucleoli is noticeable. That they are 

 composed of different material is evident from the difference in staining capacity. A 

 nematocyst [fzem.) is shown imbedded in the mass of cells. X 975- 



Fig. 2. A group of the primitive ova in which the regressive changes are just 

 started. In the cell marked (a) the chromatin is retreating toward the periphery of 

 the nucleus ; in that marked (d) the spireme is formed. The cells are a little larger 

 than the other primitive ova which are shown in the upper right hand corner. X ^5°- 



Fig. 3. The distal portion of a growing egg in which the outline of an engulfed 

 cell is clearly shown. The cell-wall appears as a well-defined line. X 850. 



Fig. 4. The fragments -'on of the nucleus of one of the cells contributing to the 

 mass of the egg. The ce' -wall has in part disappeared, while the coalescence with 

 a neighbor cell has begun. The nuclear membrane has dissolved and the chromatin 

 filaments are being scattered. Vacuoles are conspicuous in the nucleolus. X 850- 



Fig. 5. A condition not quite so far advanced as that in Fig. 4. Several meta- 

 plasmic bodies are apparent. In the cells bordering on the egg, the regressive 

 nuclear changes have begun. X ^5o. 



Fig. 6. A nourishing cell bordering on the egg. The nucleolus has broken 

 through the nuclear membrane. Within, the broken chromatin filaments are plainly 

 visible. X 650. 



Fig. 7. A young nucleus showing the single large nucleolus and several small 

 nucleoli. Chromatin filaments are evident. X ^5°- 



Fig. 8. An older nucleus in which the nucleoli are very numerous. There are no 

 traces of chromatin filaments whatsoever. X 650. 



