Beer —Studies in Spore Development . II. 723 
5*. A spindle develops, the bivalent chromosomes are drawn upon it, 
and the single chromosomes separate from one another and travel to the 
two poles of the spindle. 
6. Here they remain either almost unchanged in the daughter nuclei 
during interkinesis (Matricaria) or they may undergo partial dispersal of 
their substance ( Tragopogon , Crepis ). A condition of complete ‘rest 5 is, 
however, not reached in any of these forms. In Matricaria there is no 
vacuolation of the chromosomes at this time, but in Tragopogon and Crepis 
vacuoles do make their appearance in these bodies. In these cases the 
vacuoles may occupy the central line of the chromosomes, and thus divide 
these structures into two longitudinal halves (as in Galtouia), or quite often 
no such regular disposition of the vacuoles is to be observed and the break- 
ing up of the chromosome bodies takes place less regularly. 
7. The homotype division which follows resembles, in most respects, 
an ordinary somatic division. The halves of the longitudinally divided 
chromosomes are separated during the anaphase of this division. 
8. The somatic divisions were studied in Crepis virens , which was 
a convenient object on account of the low number of its chromosomes 
(6 somatic). Considerable variety was found to exist in the manner in 
which the chromosomes develop during the prophase of division. In 
a large number of cases this takes place by the condensation of the nuclear 
reticulum along the two sides of certain lines or bands. This gives rise to 
condensation-areas (rudimentary chromosomes), which consist of two parallel 
halves. Condensation may, however, take place differently in other cases, 
but sooner or later it leads to the formation of longitudinally divided 
chromosomes. 
9. No continuous spireme is formed during the somatic divisions. 
10. The daughter chromosomes of the somatic division are distributed 
to the poles, where they become joined together by delicate bars and fila- 
ments of chromatin and their substance undergoes vacuolization. By the 
continuation of this process the substance of the chromosomes gradually 
becomes dispersed over a delicate reticulum. No prochromosomes are to 
be seen in the resting nuclei which are in this way produced. 
In the majority of cases the vacuolation of the chromosomes takes 
place along a median line so as to divide these bodies into two longitudinal 
parts. 
There is reason to believe that this division of the chromosomes during 
the telophase may be identical with the one which so often reappears at 
the prophase of the following mitosis, and which marks the line of separa- 
tion between the daughter chromosomes which are drawn apart during the 
anaphase. 
It should be noted, however, that just as there was found to be con- 
siderable variation in the details of the condensation phenomena of the 
3 B 2 
