:\IETAP]rASI^ SPINDLE IN F(3RF[CULA AURICULARIA. 
261 
anaphase, i - e. at the moment when tlie daughter-chromosotnes 
have begun to move apart, appears to be a constant for eacli 
spermatogenetic mitosis of the species. The lengths found 
are 7*3, 10'7 and 8'3 /u for the secondary spermatogonia and 
primary and secondary spermatocytes respectively. 
(4) The ratio between the lengths of the mitotic spindle at 
the conclusion of the primary and secondary spermatocyte 
metaphases is almost identical with the ratio between the 
radii of two spheres of which the volume of one is ecpial to 
twice that of the other ; and the volume of the primary 
spermatocyte cell must be equal to twice that of the 
secondary spermatocyte at this stage, because no growth or 
resting stage intervenes. 
(5) The ratio between the lengths of the mitotic spindle 
at the conclusion of the primary spermatocyte and secondary 
spermatogonial metaphases is almost identical with the ratio 
between the radii of two spheres of which the volume of one 
is equal to three times that of the other. The initial volume 
of the primary spermatocyte cell must be half that of the 
secondary spermatogonium, because the latter divides to form 
two daughter primary spermatocytes ; but the large size of 
the last-named, observed at the close of the growth period, 
does not refute the suggestion that the initial volume is 
increased six-fold during this period. 
(6) If coincidence is not responsible for the apparent con- 
nection between the ratios mentioned above, correlation is 
■established between the cell volume and length of spindle in 
the spermatogenetic metaphases of this species. 
March, 1913. 
Bibliography. 
Gallardo, A. — “ Les theories de la division cellulaire,” ‘ Ball, de la Bib, 
Amer.,’ No. 7 (1912). 
Hartog, M. — “ The New Force : Mitokinetism,” ‘ Rep. Brit. Assoc., Sect. 
D.,’ Sheffield (1910). 
Meek, C. F. U. — “ A Metrical Analysis of Chromosome Complexes, 
showing Correlation of Evolutionary Development and Chromatin 
Thread-width thronghont the Animal Kingdom,” ‘Phil. Trans- 
Roy. Soc.,’ ser, B, vol. cciii (1912). 
VOL. 59, PART 2. NEW SERIES. 17 
