No. I.] SPERMATOGENESIS OF BATRACHOSEPS. 59 



The life cycle of the auxocyte comprises a stage of growth 

 and a stage of mitosis. During the former both cell and 

 nucleus increase in size. The stage of growth ceases as soon 

 as the cell enters the bouquet stage with twisted spireme 

 segments. 



Spermatocytes . 



The spermatocytes are the daughter-cells of the auxocytes. 

 In size they are smaller than their mother-cells. They are 

 characterized by the absence of the bouquet stage, by the 

 homoeotypic mitosis, by twelve chromosomes, which are thrown 

 on the central spindle in the shape of F's. The chromosomes 

 are borne in the form of staples or horseshoes and gradually con- 

 tract to Vs. There is only one generation of spermatocytes. 

 The mitosis is by equation division, in which they resemble the 

 auxocytes. The daughter-cells of the spermatocytes are the 

 spermatids. We can distinguish the following stages. 



Chrysanthemum Stage, in which the chromosomes have the 

 form of staples, arranged like the petals of a chrysanthemum 

 flower (Figs. 62-70). 



Checkerboard Stage, in which the chromomeres have sepa- 

 rated and become more or less evenly distributed over the 

 nucleus. Resembles a checkerboard (Figs. 71-82). 



Contraction Stage, in which the chromosomes again contract 

 into staple-shaped chromosomes (Figs. 83-86). 



Angular Chromosomes. — In this stage the chromosomes 

 become narrower, straighten out, and cross each other at 

 various angles. The chromomeres also become so fused as to 

 be scarcely distinguishable one from the other. This stage 

 corresponds to the angular stage of the auxocytes. 



Knotted Chromosomes. — In this stage the chromosomes are 

 thrown in the center of the cell in a knot, in which the indi- 

 vidual chromosomes are so mixed up as to be only recognized 

 with difficulty (Figs, 88-91, 94-97). 



V-Metaphase. — The perfect and split and F-shaped chro- 

 mosomes are on the equatorial of the central spindle (Figs. 99- 



lOl). 



V-AnapJuxse. — (Figs. 102, 103). 



