Nachdruck verboten. 

 Uebersetziaigsreckt vorbehalten. 



Tlie Spermatogenesis of Peripatiis (Peripatopsis) balfouri 

 up to the Formation of the Spermatid. 



By 

 Thos. II. Montgomery jr., Ph. D., 



Assistant-Professor of Zoology, University of Pennsylvania, Philadelphia, Ü, S. A. 



With Plates 19—25. 



Contents. 



Introduction. 

 I. Material. 

 n. Structure of the male genital organs. 



1. Testis. 



a) Sheath of the testis. 



b) Fibre-cells of testis. 



c) Distal end of testis. 



2. The seminal vesicle. 



3. The vas deferens. 



III. Spermatogonia and their mitoses. 



1. Rest stage. 



2. Mitosis up to the metakinesis. 



3. Metakinesis. 



IV. Anaphases of the last spermatogonia mitoses. 



1. Early anaphases. 



2. Synapsis stages. 



3. Telophases. 



V. Rest stage of the spermatocytes. 

 VI. Maturation mitoses. 



1. Prophases. 



a; Idiozome and centrosomes. 

 b) Nucleus. 



2. Monaster stage of the 1st spermatocytes. 



3. Metakinesis and dyaster of the 1st spermatocytes. 



4. Second maturation mitosis. 



5. Structure of the spermatozoon. 

 YII. The giant spermatogonia. 



VIII. Number of chromosomes in cells not of the sperm?itogenetic series. 



