110 
L. Digby 
Resting nuclei of Tapetum. 
A critical study of ‘restiug’ nuclei has been made from the tapetum, 
as uuclei in typical ‘rest’ are not to be found m the rapidly dividmg arche- 
sporial tissue. Overto^" (40) observed that ‘prochroniosomes’ were onlv 
present in “gut ernährten Zellkenien” (p. 124), a condition characteristic 
of tapetal cells, which should accordingly be a favourable tissue for ‘pro- 
chroniosoine’ investigation. 
In a completely resting tapetal nucleus, the hnin forms a fme colour- 
less reticulum which is arranged peripheraUy. The nucleolus stains deeply, 
and apparently the enth'e chromatic contents of the nucleus are con- 
fined to the nucleolus and to the deeply staining chromatic bodies. These 
bodies are fe^y in number and niay probably not exceed six. The nuclei 
selected for cb•a^Ying sliow severally one (PI. X, fig. 118), two (fig. 119) 
and three (fig. 120) chromatic bodies. There are often sniaU granules and 
faintly staining aggregations aniongst them, wliose nature it is difficult 
to determine. It is apparent, therefore, that the number of cliromatic 
bodies in the resting nuclei of the tapetum is variable, and is constantly 
lower than that of the somatic chromosomes. 
Eosexberg (46) has figured a resting nucleus of Crepis virens (Tafel 1 
fig. 1) taken from the peduncle (Blütenstandachse) showing a colourless 
reticulum and six definite ‘prochromosomes’. Ei this comiection he 
writes “Im Kuhestadiiun des Kerns ist es auffallend, wie wenige ‘Chro- 
matinkörner’ im Kern enthalten sind. Ich habe darum auch ohne Schwie- 
rigkeit die Anzahl der Prochromosomen auf 6 feststeUen können” (p. 66). 
Xuclei with six chromatic bodies may be found, but just as ofteii nuclei 
witii less than six. 
Similar variable results have been obtamed from the study of resting 
poUen mother -nuclei before the onset of the heterotype prophase, and 
from the resting tetrad. Consequently it is not possible to bring the 
results of this investigation into hne with any far reaching conclusions 
based on the assumption that the number of the bodies is constant, and 
is identical with that of the chromosomes. 
The meiotic phase. 
The foregoing description of the telophase, interkmesis, and early 
prophase stages of archesporial mitoses, has been taken exclusively from 
immature buds whose anther walls consist of but one or two parietal 
layers of cells. 
In tracmg the telophase of the last archesporial division into the 
‘rest’ which precedes the heterotype prophase, some difficulty has been 
