Vol. XXXIV. May, 1918. No. 5 



BIOLOGICAL BULLETIN 



SPERMATOGENESIS OF THE PACIFIC COAST 

 EDIBLE CRAB, CANCER MAGISTER DANA. 



NATHAN FASTEN, 

 DEPARTMENT OF ZOOLOGY, UNIVERSITY OF WASHINGTON, SEATTLE. 



CONTENTS. 



1. Introductory Remarks 277 



2. Material and Methods 278 



3. Description of Testis 279 



4. Spermatogenesis 280 



A. Spermatogonial Stages 280 



B. Primary Spermatocyte Stage 283 



(a) Growth Period 283 



(b) Reduction Division 285 



C. Secondary Spermatocyte Stage 287 



D. Transformations of the Spermatids into Spermatozoa 288 



5. Opening of the Mature Spermatozoa 293 



6. Discussion 294 



A. Synapsis 294 



B. The Chromatoid Bodies 295 



7. Summary 296 



8. Bibliography 298 



9. Description of Plates : 300 



i. INTRODUCTORY REMARKS. 



The Decapoda have always been of absorbing interest to the 

 cytologist and considerable has been written concerning their 

 germ cells. In a previous publication ('14), I have given a 

 review of the important literature on the subject, and by re- 

 ferring to this article it becomes apparent that practically all 

 the investigations have been confined to the male reproductive 

 elements of the Macrura and Anomura. Virtually nothing has 

 been done with the Brachyura; in fact there isn't a single com- 

 plete spermatogenesis of a crab known. Carnoy ('85) observed 

 and pictured a few of the early proliferation stages in the sper- 



277 



