924 THE AMERICAN NATURALIST. [Vor. XXXV. 
spermatogenesis of the arthropods. In some respects my 
observations agree with his; in others they differ. 
The nuclei of the spermatids in Oniscus undergo a gradual 
elongation and condensation. During this process the cell 
; walls between adjacent spermatids dis- 
appear and groups of nuclei are formed 
lying in a common plasma. Within the 
latter arise bundles of fibres of great length. 
Gilson in his Fig. 320 shows a direct con- 
tinuity of these cytoplasmic fibrils with 
the elongated nuclei. That such a con- 
nection actually exists I have been unable 
to convince myself. In addition to the 
bundle of fibres there are single fibres of 
. greater delicacy which are continuous with 
the nuclei. The appearance of the mature 
sperm colony may be seen from Fig. 6. 
Figs. 7 and 8 represent longitudinal and 
transverse sections of immature colonies. With Wilcox’s double 
stain of saffranin and malachite green the cytoplasmic fibres 
stain green and are thus sharply differentiated from the nuclei, 
which stain red. In cross-section the nuclei are seen as a circle 
of red dots surrounding a group of green 
dots, the cytoplasmic fibrils. In examining a y 
a series of sections from the nuclear region 
towards the flagellum, the group of green ,^—c i gi 
dots in the center eventually ceases to be (38+ ; 
visible, and the surrounding red dots grad- 
ually merge into converging green fibres tS pec ener 
of great delicacy (Figs. 7 and 8). "The  prenuclear region; 4 and <, 
evidence at my disposal admits of two pede oo 
interpretations, — either the long bundle 
of cytoplasmic fibres stops abruptly before the anterior end 
of the bundle is reached, and they thus have no connection 
with the nuclei, or the connection is of such a character as 
to escape observation. Since the structures concerned are 
extremely minute and delicate, the latter might easily be 
the case. 
l 
andit à fibre res 
