132 
L. Digby 
reasons for regarding these chromatic bodies as expressions of mere chrom- 
atic concentration. 
Firstly, they vary in number, in size, and in development, and secondly, 
as expressly pointed out by Gregoire (20), Tischler (60) and Laibach 
(26), the entire chroniatic contents of the nucleus is not always concen- 
trated in tbese bodies, but the residue may be distributed throughont 
the reticuluni often marking the angles of the meshes. 
For this reason sonie cytologists have objected to the name ‘pro- 
chroinosome’. Laibach (26) and Kosexberg (47) have suggested the terni 
‘Chromozentren’. Rosexberg States that although he has been able to 
show that in some plants the ‘Körper’ may appear in resting nuclei in 
the number of the chromosomes, yet he does not consider that the name 
‘prochroniosonie’ aptly describes them. “Diese Benennung ist entschieden 
nicht die glückhchste und ich fühle mich oft versucht, andere Namen vor- 
zuschlagen, etwa Chromozentren oder dgl, die eigenthch nichts anderes 
aussagen soUen, als daß die chromatische Substanz des Kerns bei ihrer 
Entstehung in den Prophasen von gewissen Zentren ausgeht” (p. 163). 
Luxdegardh (29) considers that the chroniatic aggregations should rather 
be temied ‘Prochromosomenteüe’ than prochromosomes, because the 
aggregations are frequently more numerous than the chromosomes. 
The results of this investigation of the resting nuclei of Crepis virens 
confirm the \’iew that the chromatic bodies are merely expressions of chrom- 
atic concentration, and are not ‘prochromosomes’ in the strict sense of 
that term. 
II. The evolution of the heterotype chromosomes. 
Farmer (12) has recently drawn attention to the confusion attending 
the terms ‘telosynapsis’ and ‘parasynapsis’, used as signifying the nianner 
of pairing of soniatic chromosomes m preparation for the heterotype 
division. AMiether the somatic chromosomes are associated end to end 
or side by side in the spireme, is a matter of little importance, and it is 
generally agreed that both arrangenients do occur. The fundamental, 
and important difference which is involved, rests ou the interpretation 
to be placed on the presynaptic phases. Those who advocate the telo- 
synaptic theory regard the paraUelisms of the heterotype presynaptic 
prophases as honiologous with those of the somatic prophases, and 
consequently as representing the condensation of two longitudinal 
halves of a single soniatic chromosonie derived from the pre- 
ceding telophase; whilst those who advocate the parasynaptic theory 
regard the paraUeÜsms of the heterotype presynaptic prophases a& re- 
