596 
J. BRONTE G ATEN BY. 
observers. It is that these rods are the condensed spindle, 
and that their supposed disappearance before mitosis is due 
to the fact that they have gone to form the astral figure. 
As far as the snail is concerned 1 am somewhat doubtful as 
to the validity of this interesting suggestion. Without 
definitely condemning or upholding this view I think that 
the following facts should be borne in mind. In the 
Helicids : 
(1) It is, if not absolutely unproven, at least extremely 
doubtful whether the rods do disappear 1 (PI. 32, figs. 23 and 
27). 
(2) The substance of the rods differs in bulk, as also do the 
number of the rods. Variation in the size of the spindle is 
almost negligible (Figs. 24 a and 36, Figs. 25 and 32, etc.). 
(3) In the prophases the rods can undoubtedly be found 
lying here and there in disorder, not as if they served a defi- 
nite function in the formation of the amphiaster. 
(4) In many spermatogonial late telophases the Nebenkern 
appears in a position removed from the centrosome, archo- 
plasm, or spindle bridge. Not in any case as if it appeared 
to be reinstated by a condensation of any part of the amphi- 
aster (PL 32, fig. 29). 
(5) In numerous other animals the spindle appears and 
disappears without a Nebenkern (batonettes). 
(6) Bolls Lee and I describe a triradiate structure from 
which the astral rays arise, and which is undoubtedly un- 
related to the Nebenkern (PI. 33, fig. 33). 
(7) Spermatogonial generations are to be found in which 
the cells before entering mitosis had no definite Neben- 
kern. 
Before the spindle-forming function of the Nebenkern can 
be proven all these objections must be met. I do not think 
any of them can be explained satisfactorily from the point of 
view of the observers who espouse the theory. Term's state- 
ment already mentioned, that he did not believe that all the 
1 In a forthcoming paper I have described how to fix and stain so as 
to show these rods during metaphase. 
