MITOSIS OF 

 SECONDARY 

 SPERMATO- 

 GONIUM 



MEIOSIS BEGINS 



LEPTOTENE 



SEX CHROMOSOME 



Z YG OTENE 



PACHYTENE 



Dl PLO T E N E 



FIRST 



MATURA TION 



DIVISION 



SECOND 



MATURATION 



DIVISION 



SPERMIOGENESIS 



TRA NSFORMATION 

 OF SPERMATID TO 



SPERM Y 



PICAL CELL WITH PRIMARY 

 SPER M ATOGONIA 



RIOD OF MULTIPLICATION 

 SECONDARY SPERMATOGONIA 

 DIVIDE MITOTIC ALLY 



E R lOD OF GROWT H 



PRIMARY SPERMATOCYTES 

 INCREASE IN SIZE WHILE IN 

 SUCCESSIVE STAGE S OF 

 PROPHAS E 



APICAL OR NURSE 

 CELL 



FIRST MATURATION DIVISION 



PRIMARY SPERMATOCYTES FORM 

 SECONDARY SPERMATOCYTES 



SECONDARY MATURATION DIVISION 

 SECONDARY SPERMATOCYTES 

 FORM SPER MATI D S 



- PERIOD OF TRANSFORMATION 

 SPERMATID CHANGED TO 

 SPERM 



Fig. 69. Steps in spermatogenesis in the grasshopper. In the center of the chart is 

 represented a longitudinal section of one of the follicles of a grasshoper testis with its 

 various regions of spermatogenic activity. In the upper right of the chart the apical-cell 

 complex is depicted with its central apical cell, spermatogonia, and surrounding epithelial 

 cells. The primary spermatogonia lie enmeshed between the extensions of the apical cell 

 and the associations of these extensions with the surrounding epithelial elements of 

 the complex. (Also see Wenrich, 1916, Bull. Mus. Comp. Zool. Harvard College, 60.) 



131 



