234 w - M - SMALLWOOD. 



EXPLANATION OF PLATES. 

 EXPLANATION OF PLATE I. 



FIG. I. Egg nucleus with small amount of cytoplasm to show the migration of 

 the chromatin. A r / / , nucleus ; AW, nucleolus ; chr, chromatin. 



FIG. 2. Portion of the cytoplasm and nucleus. The chromatin is mostly in vacu- 

 oles. Nl> ', nucleus ; chr, chromatin. 



FIG. 3. Prophase first maturation. The walls of the nucleus are still intact. 

 The egg is within the gonophore. E. A T l f , egg nucleus ; w. g, wall of gonophore. 



FIG. 4. Telophase of the second maturation. Egg deposited. Cl. pol 2 , second 

 polar body; vsl. c/ir'so, chromosome vesicles. 



FIG. 5. Female pronucleus showing the remains of fibers that have persisted. 

 Pronl. 9 > female pronucleus. pr. gr, peripheral granules. 



Fic. 6. The approach of the male pronucleus. The female pronucleus is in 

 the early prophase. Pronl. 9 > female pronucleus ; pronl. $ , male pronucleus. 



FIG. 7. Prophase of third cleavage shows an elongated nucleus with asters and 

 forming spindle fibers. 



