142 
Dig by . — On the A rchesporial and 
telophase or prophase. It might be expected that, as in the earlier arche- 
sporial divisions, the position of the recently laid down cell-wall, separating 
the daughter nuclei, would be a guide to the solution of this problem ; 
but, owing to rapid growth, nuclei undoubtedly in heterotype prophase 
may be closely apposed to the wall. The following observations have been 
found to be of some assistance in distinguishing the phases : 
(1) The size and shape of the nucleus maybe useful, but not infallible, 
guides. During late telophase and early rest, the nuclei are, as a rule, more 
or less spherical, and of relatively small dimensions ; as prophase proceeds 
they increase proportionately in volume, and tend to become ovoid in form. 
(2) A nucleus in telophase has a somewhat definite limiting membrane, but 
its contour fades away during rest, thus causing the nuclear outline to blend 
with the surrounding cytoplasm. During prophase the limiting membrane 
is still indefinite, but the brightly staining contents of the nuclei cause them 
to stand out in sharp relief. (3) There may be three or more nucleoli in the 
telophasic stages, but in definite prophase there are seldom more than two. 
(4) In telophase a clear space, traversed only by isolated threads, is con- 
stantly present round each nucleolus, whilst in prophase the nucleoli are 
more or less entangled in the reticulum. 
In the light of these remarks it will be seen that it is not practicable to 
come to a conclusion with regard to the definition of the stages represented in 
PI. VIII, Fig. 30, and PI. IX, Figs. 31, 32, and 33. The paired beaded threads 
(PI. VIII, Fig. 30) are typically telophasic as compared to the pairing of more 
or less homogeneous threads in prophase. This pairing is very evident in 
the superficial section (PI. IX, Fig. 31) taken from the same sporangium as 
Fig. 30. The three nucleoli and the more or less clear spaces surrounding 
them are also suggestive of telophase. On the other hand, the large size of 
the nucleus and its active appearance indicate prophase. A somewhat 
similar stage is shown in Fig. 32, but in this case little evidence remains of 
paired beaded threads, though the groupings of the beads in twos or fours 
and the disposition of the fine linin threads indicate parallel arrangements. 
These figures have been intercalated to show the impossibility of 
identifying certain phases, but, on the other hand, it is feasible to follow out 
a definite sequence in the passing of telophase into prophase as shown by 
Figs. 29, 33, and 36. Fig. 29 is a more or less typical late telophase, 
the chromosome halves (threads) having fragmented into chromatic beads, 
leaving spaces round the two nucleoli. It is believed that such a nucleus 
may either proceed directly through an intermediate stage (Fig. 33) into the 
heterotype prophase (Fig. 36) or may pass through an intermediate rest 
(Fig. 34). In this particular instance the former is probably its course, for 
Fig. 33, a nucleus unquestionably in a stage transitional between telophase 
and prop-hase, is taken from the same sporangium and even from the same 
microscopic field as Fig. 29. 
