B. F. Kingsbury 1^'^ 



the figures 1-6 of Plate 1. The exact method of chromatin change 

 during the establishment of the chromosomes is rather difficult to deter- 

 mine. The chromatin of the spermatogonium seems to migrate out on 

 the linin network as small granules and accumulate in lines as the spirem 

 threads (or thread). Just in how far there is an actual migration ot 

 particles and how far it may represent a chemical change, as of the less 

 chromatic particles to the more chromatic and the reverse (e. g., as the 

 change of oxychromatin to basichromatm of Heidenham), giving the 

 efEect of such a migTation, could not be detected. 



Eisen, oo, in his richly illustrated contribution upon the spermato- 

 genesis of Batrachoseps, devotes attention largely to the finer structure 

 of the cells. My work upon the minute details has been insufficient to 

 render a full criticism of Eisen's views justifiable. Chromioles, chromo- 

 meres and chromosomes (his terminology) are recognized, and it seems 

 highly probable that the chromioles do unite to form the chromosomes, 

 though not in the fantastic way he describes. Chromoplasts were not 

 recognized, and in the "bouquet" stage, instead of twelve "leaders" 

 there are twenty-four, as may be seen from the transection, Eig. 4. In 

 other words, one "wreath" does not represent two chromosomes joined 

 by a chromoplast, but a single chromosome bent m the form of a horse- 

 shoe. Although the term "Auxocyte" was introduced by Lee as a 

 name for the spermatogonium which becomes the spermatocyte of the 

 first order, he fails to use it in his main work on the spermatogenesis of 

 Helix and its introduction does' not simplify nomenclature, especially 

 when it is applied to the spei-matocyte of the first order, either mature or 

 in any stage of its growth. 



It seems quite certain that there is not in this period of growth any 

 formation of twenty-four chromosomes which then actually unite to 

 form twelve; nor does it seem probable that a single continuous spirem 

 is formed, which subsequently segments into the twelve chromosomes, 

 though, as already stated, this is possible. The process appears as one 

 of a continuous change and growth by which the distributed chromatin 

 is gathered together in the form of twelve loops. In this case synapsis, 

 actual or potential, would not occur as an observable fact. 



But little attention has been bestowed upon the achromatic structm-e 

 of the nucleus or cell body at this stage. The increase in the size of the 

 cell body is quite large, as may be seen by comparing the figures 1-b. 

 The idiozome, with the two centrosomes contained, shows usually three 

 zones, which are, however, ill defined. In tissue fixed in chrom-aceto- 

 osmic mixture there is a condensation of substance about the idiozome, 

 as Eisen has figured it in BatracJioseps. This is not shown in tissue 



