220 
Kristine Bonnevie 
Textfig. M. 
Den Verlauf der ersten Keifungsteilung werde ich mit Griffixs 
eigenen Worten hier zuerst skizzieren; 
(S. 605.) »While entering the spiudle in the prophases, the chromo- 
somes exhibit a great variety in forms, which in most cases are 
easily reduced to the type of a double rod«. 
(Es folgt dann eine Beschreibung der verschiedenen in Textfig. M 
hier reproduzierten Chromosomenformen.) 
(S. 607.) »From the complete failure to find forms indicating a 
direct transformation of the open rings 
into the metaphase figures, it seems 
not improbable that the thick rods may 
represent a later and more concentrated 
Stage of the rings«. . . . »The open 
ring, however, is not to be considered 
a necessary stage, for it is quite evident 
that many of the rods arise directly 
from the similar structures present in 
the germinal vesicle. 
More diflficult to determine are the 
occasional two short rods lying side by 
side {k, l, w^) as well as crosses or 
ophiurid forms (?^) the arms of which 
appear perfectly solid without the slight- 
est indication of a division into halves «... 
»Despite the varied forms presented 
during prophase, the chromosomes of 
the equatorial plate exhibit considerable 
uniformity. Hence the various prophase 
forms must in some manner be convertible into a uniform type of meta- 
phase figure. The commonest and, as we shall consider it, the typical 
form assumed by the chromosomes in the latter stage is that of a 
cross, with a pair of broad arms in the equatorial plane, and the 
narrower perpendicular arms directed toward the poles of the division 
figure« (Textfig. N, o — s]. 
(S. 609.) »The crosses are to be derived from the double rods 
by a swelling or looping up of the halves in the middle. The be- 
ginning of the process is represented by the previously described 
thick rod with a central bead-like swelling. In a slightly later stage, 
a central hollow appears which, separatiug the sw’elling into two 
knobs, shows the rod to be double« (o, «, v). 
Chromosomenformen aus der Prophase der 
ersten KeifungsteUung von Tliatassema. 
(Nach Griffi!;.) 
