138 KANSAS UNIVERSITY QUARTERLY. 



TERMINOLOGY. 



The terminology used in this paper will be made to conform as 

 nearly as the case allows to that in general use. The terms sper- 

 matogonia, spermatocyte, spermatid and spermatozoon will be used 

 with their usual significance. In addition to the cells ordinarily in- 

 dicated by these names, others will require consideration which are 

 analogous to the '"sex sells*' of Voight and Semper, the "primordial 

 metrocyte" of Biondi, the "germinal cells" of Balfour and von Ebner, 

 the "primitive male ovule" of St. George and others, the "grosse 

 Spermatogonien"" of Meves, and the "primary spermatogonia" of Mc- 

 Gregor. The latter term, which indeed I had considered before the 

 appearance of McGregor's paper, is very suitable for these cells, and, in 

 connection with the name "secondary spermatogonia,^' for the deriva- 

 tive cells occurring in cysts (as also employed by the same author), 

 will be used in this paper. 



The different phases of a single cycle of division will be designated 

 in the usual way, as prophases, metaphase, anaphases, and telophases, 

 and, in order to avoid the confusion which sometimes arises from the 

 slightly different ground which various authors are accustomed to 

 cover by these terms, I will define their extension as used by me for 

 this object. 



The moment when the chromatin of the daughter-cell has reached 

 the greatest degree of diffusion, and from which it commences to take 

 on the form of a spireme, will be regarded as the dividing line be- 

 tween the telophase of one generation and the prophase of the next. 

 This is the logical place for the division line between cycles, since the 

 disintegration of the chromosomes of the daughter-cell is to be re- 

 garded as a mere restoration of the metabolic condition of the chro- 

 matin after the necessary assumption of the condensed form for the 

 purpose of division. The prophases will include all conditions of thf 

 cell from the point named to the metaphase, in reference to which 

 there is no uncertainty. The anaphases will cover all stages from the 

 beginning of the separation of the chromosomes at the equatorial 

 plate to their arrival at their destination about their respective cen- 

 trosomes. The telophases will begin at this point and extend to the 

 end, of the cycle as already designated. 



As to the extension of the different generations of testicular cells, 

 only two will need to be defined, namely, the primary and the sec- 

 ondary spermatogonia. 



Of the former I have seen but one generation in BracJiystoIa, as I 

 was able to obtain only adult material. However, in the formation of 

 the testes in Arp/iiti. I have observed the earliest follicles to be com- 

 posed exclusively of them, and the growth of the follicles, and conse- 

 quently of the testis, to be accomi)lished by their mitotic division. 



