No. I.J SPERMATOGENESIS OF BATRACHOSEPS. 



6l 



/. Polymorphouj Spermatogonia} 



2. Round Cell 

 6p erma to gonia. 



5. Round Ceil 

 Spermatogonia. 



4. Round Cell 

 Spermatogonia. 



5. Round Celt 

 Spermato- 

 gonia. 



Explanation of the Diagram of the Various Generations of Cells in the Testes of Batra- 

 choseps. 



1. Polymorphous spermatogonia, with polymorphous nucleus, somatic mitosis with twenty-four 

 chromosomes. The daughter-cells of these spermatogonia constitute the following generations 2-5. 



2. Spermatogonia with round nucleus, somatic mitosis with twenty-four chromosomes. The 

 daughter-cells of the polymorphous spermatogonia. There are several generations in rapid succes- 

 sion, and apparently all alike. These generations are as follows : 



3. Spermatogonia with round nucleus similar to No. 2. 



4. Spermatogonia with round nucleus similar to No. 2. 



5. Spermatogonia with round nucleus similar to No. 2. 



6. Auxocytes, the daughter-cells of the last generation of round nucleated spermatogonia. The 

 change which caused a mitosis with twelve chromosomes takes place in the resting stage. The auxo- 

 cytes are characterized by twelve chromosomes, a bouquet stage, and a heterotypic mitosis. Equa- 

 tion division. Fiber cones after the anaphase. One generation. 



7. Spermatocytes with twelve chromosomes, the daughter-cells of the auxocytes. Characterized 

 by the absence of a bouquet stage. Fiber cones with certainty only in the prophases, homoeotypic 

 mitosis and equation division. One generation only. The daughter-cells of the spermatocytes are 

 the spermatids. 



8. Spermatids. 



9. Spermatozoa. 



