264 C - W - METZ. 



EXPLANATION OF PLATES. 



All figures were drawn from sections 5 in thickness, with the aid of a 

 camera lucida. Magnification approximately 3,000 diameters. 



PLATE I. 



All figures except numbers i and z are from Dasyllis grossa ; numbers i 

 and 2 are from specimens not yet identified as to species. 



FIG. i. Spermatogonial metaphase. 



FIGS. 2 and 3. Spermatogonial prophases. 



FIG. 4. Very early growth stage, only one aggregate or chromosome pair 

 represented. 



FIG. 5. Same stage, representing portion of another aggregate. 



FIG. 6. About the same, or slightly later stage, showing two aggregates. 



FIG. 7. Slightly later stage after the chromosomes have moved to periph- 

 ery of nucleus. One chromosome pair and attached dense body represented. 



FIGS. 8 TO 10. Similar stages showing other chromosomes. The chromo- 

 some pair on the left in Fig. 9 is presumably the small pair which usually 

 has no loop or a very small one. 



FIG. n. Later stage, about middle of growth period. Entire nucleus 

 represented, including the four pairs of autosomes and the small, condensed X. 



FIG. 12. Later stage, entire nucleus; chromosomes transposed to facili- 

 tate examination. 



