No. 3. — The Spermatogenesis of Phrynotettix magnus, with special 

 Reference to Synapsis and the Individuality of the Chromosomes. 



By D. H. Wenrich. 



contributions prom the zoological laboratory of the 

 museum op comparative zoology at harvard 



COLLEGE. No. 266. 



TABLE OF CONTENTS. 



I. Introduction 



A. Outline of the problems 



B. Material and acknowledgments 



II. Observations 



A. Outline of spermatogenesis: nomenclature 



a. Introductory ..... 



b. Outline of successive stages 



1. 



2. 



3. 

 4. 

 5. 



Spermatogonia 

 Primary spermatocytes 

 Secondary spermatocytes 

 Spermatids 

 Spermatozoa 

 c. Additional features 



B. Synapsis 

 a. The postspireme stages 



1. Chromosome-pair A 



2. Chromosome-pair B 



3. Chromosome-pair C 

 h. The conjugation of chromosomes . 



1. The formation of leptotene threads 



2. The zygotene stages 



3. The pachytene stages 



C. The individuahty of the chromosomes . 



a. The selected chromosome pairs 



1. Chromosome-pair A 



2. Chromosome-pair B 



3. Chromosome-pair C 



b. The accessory chromosome 



c. The spermatogonia! divisions 



d. The somatic nuclei 



D. Summary of observations 



PAGE. 



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