238 B. F. KINGSBURY AND PAULINE E. HIRSH 



introduces for consideration in this connection one of the critical 

 stages of oogenesis and spermatogenesis which appeals to the 

 writers as one of the most difficult of interpretation^ — the so- 

 called synapsis staged 



The suggestion then tentatively made^ was that the resemblance 

 between the nuclei in synizesis and the degeneration under con- 

 sideration might be more than a superficial one, especially as they 

 both occurred at about the same time, associated apparently with 

 the end of the multiplication period; that synizesis itself might 

 possibly represent a 'running out of the spermatogonial stock.' 

 Synizesis would on this interpretation be a 'beginning degenera- 

 tion' — with recovery, which passes over later in the season into 

 a degeneration leading to dissolution. 



The following diagram or schema may serve to illustrate for 

 the form Desmognathus the comparison of synizesis and the 

 degenerations in question. Successive stages in the spermato- 

 genesis being indicated by the letters of the alphabet as given in 

 the legend below, while the idealized zones of the testis are num- 

 bered from 1 to 10. 



- The terminology employed in the discussion of this period of the gametogenesis 

 possibly calls for brief comment. Synapsis is used in the original sense of the 

 pseudo-reduction in the chromosome number interpreted as due to a joining 

 together in pairs. It is therefore as used here equivalent with conjugation and sj^n- 

 desis. For the contraction of the nuclear contents the term Synizesis introduced 

 by McClung is employed. While synapsis and synizesis are usually reported as 

 occurring together at the beginning of the growth period of the spermatocyte, after 

 the last spermatogonial division, they are not in all cases so assigned. Mont- 

 gomery places synapsis in the telophase of the last spermatogonial division. Miss 

 King described it in the toad as occurring after the growth period of the spermato- 

 cyte, etc. 



^ Page 108. " (c) when the spermatogonia cease to undergo transformation 

 into spermatocytes in the summer, the last cysts of spermatogonia apparent I3' 

 undergo a chromatolysis and solution, and the boundary between the spermato- 

 cytes which are to form spermatozoa that season and the spermatogonia remaining 

 over until the next summer, is thus well marked." Page 111. "It is suggested 

 therefore that the contraction figures [i.e., synizesis], instead of being construc- 

 tive and a fundamental phenomenon in the formation of the spermatocyte, ma}' 

 be an expression of a 'running out' in the spermatogonium stock and represent a 

 tendency toward degeneration. We know as yet too little of the occurrence of the 

 contraction figures in different forms to draw any general conclusions; possibly 

 quite different phenomena may be here included." 



