1910.] NATURAL SCIENCES OF PHILADELPHIA. 327 



Figs. 173 and 174 — First spermatocyte, stages in prophase. 

 Fig. 175 — First spermatocyte, equatorial plate, 29 chromosomes, mito- 

 chondria and chromatin granule in cytoplasm. 

 Fig. 176 — First spermatocyte, metaphase. 

 Figs. 177 and 17S — First spermatocyte, anaphase. 

 Fig. 179 — First spermatocyte, telophase. 

 Fig. 180 — First spermatocyte, telophase, polar view. 

 Fig. 181 — Second spermatocyte, equatorial plate. 

 Fig. 182 — Second spermatocyte, metaphase. 

 Fig. 183 — Second spermatocyte, anaphase 

 Fig. 184 — Second spermatocyte, telophase. 

 Fig. 185 — Spermatid, second stage. 

 Figs. 186-190 — Spermatid, development. 



