312 Mottier . — The Development of the Heterotypic 
does not contain any material capable of being stained by known methods. 
It may frequently happen that the nucleolus or nucleoli may lie in contact 
with portions of the chromatin or linin threads. In Fig. 3 the chromatin 
is aggregated into irregular, granular shreds, giving a picture strikingly 
different from that of Fig. 4. These two cells were drawn from the same 
loculus of the anther and from the same section. In a number of prepara- 
tions, nuclei of cells in about one-half of the loculus presented the structure 
shown in Fig. 4, while in the other half, that in Figs. 1 and 3 prevailed, with 
all intergrading stages between. The cytoplasm in Fig. 4 is small-meshed 
and finely granular, giving a rather dense and finely granular appearance. 
In Fig. 3, a coarser and looser reticulum is present, and in Fig. 1 the 
fibrillar reticulum is still looser but very sharply defined and beautiful. 
There can be but little doubt that these nuclei are in about the same or in 
closely related resting stages ; for all three conditions are found in the same 
loculus. In many preparations of the same stage of development of the 
anther, about all the nuclei possessed the type of structure shown in Fig. 1. 
This structure is more frequently met with in the developing sporogenous 
tissue of young anthers and also in purely vegetative cells, yet a more finely 
granular state of the chromatin is likewise to be found in vegetative cells. 
In the preparations from which these figures were drawn, there was nothing 
to indicate poor fixation ; the cells seemed perfectly fixed and normal in 
every respect. There is, of course, a possibility that the difference here 
manifested in the disposition of the chromatin may be due to the effect of 
the fixing fluid, especially the part played by the osmic acid, but as to this 
the writer is not prepared to speak definitely at present. As will be shown 
later, it is after all a matter of comparative insignificance whether the 
chromatin occurs in larger or smaller masses or granules in the resting 
nucleus. 
Overton does not find favourable evidence in behalf of the pro- 
chromosome theory in Podophyllum . He states (’ 05 , p. 130) that ‘ in 
Podophyllum peltahim the prochromosomes are not recognizable as such. 
They may be represented by groups of chromatin masses which are con- 
nected by linin threads and arranged in parallel rows during the reticulation. 
These chromatin masses are distributed upon linin threads running parallel 
to each other, and, as in Hellehorus foetidus , there are found two distinct 
and independent spirems, which pass into synapsis unpaired and un fused.’ 
Overton supports this statement in his Figs. 53 and 54 (l.c., ’ 05 ). In these 
figures are shown parallel linin threads upon which are arranged at rather long 
intervals pairs of chromatin masses. The nuclei from which such figures were 
drawn must occur very rarely, for among a large number of preparations of 
Podophyllum no nuclei were found with parallel linin threads arranged 
in such diagrammatic regularity. Overton either did not find or overlooked 
entirely such stages as figured in my Figs. 1, 2, 3, 4. In his Fig. 5, which 
