Fig. 14S. 



Gametogenesis. A. — Parascaris equorum ; Spermatogonium (show- 

 ing intranuclear centrosome, mitochondria, refringent corpuscles 

 with golgi bodies, and nuclear contents). B. — Parascaris equorum; 

 Early prophase of 1st. spermatocyte (extrusion of intranuclear 

 centrosome ) . C. — Parascaris equorum ; Late prophase of 1st 

 spermatocyte. D. — Parascaris equorum; Metaphase of 1st. spermato- 

 cyte. E. — Parascaris equorum; Late metaphase of 1st. spermato- 

 cyte (centrosomes dividing). F. — Parascaris equorum ; Anaphase 

 of 1st. spermatocyte. G. — Parascaris equorum; Early telophase of 

 1st. spermatocyte. H. — Parascaris equorum; Telophase of 1st. sperm- 

 atocyte (centrosomes divided). I. — Parascaris eqxtorum ; Late pro- 

 phase of Ilnd. spermatocyte. J. — Parascaris equorum; Metaphase 



of Ilnd. spermatocyte. K. — Parascaris equorum ; Telophase of 

 Ilnd. spermatocyte. L. — Parascaris equorum; Early spermatid 

 I cytoplasmic lobe forming ) . M. — Parascaris equorum ; Later 

 spermatid ( cytoplasmic structures indicated). N. — Parascaris 

 equorum ; Spermatid (cytoplasmic reduction completed). O. — 

 Parascaris equorum; Oogonium of last generation (intranuclear 

 centrosome). P. — Parascaris equorum ; Late prophase of 1st. 

 oocyte (penetration of spermatozoon). Q. — Parascaris equorum; 

 Prophase of 1st. oocyte (sperm with divided centrosome). R. — 

 Parascaris equorum; Late prophase of 1st. oocyte. S. — Parascaris 

 equorum; Metaphase of 1st. oocyte ("tetrad" formation). T. — 

 Parasraris equorum; Telophase of 1st. oocyte. All drawings original. 



207 



