314 
Di L. SOÓS 
to Bonnevie (13, 14) are split after the first maturation division, but 
the chromosomes of Enteroxenos are also divided earlier. 
The first maturation division is succeeded either immediately by 
the second one, or a shorter or longer resting period is intercalated 
between them. In the first case the formation of the second maturation 
spindle begins at the moment when the first spermatocytes arrives at 
the last period of the anaphase, and when the fibres of the first spindle 
are yet in full vigour. The mode of the division is seen on the Fig. 4., 
Pl. X., and Fig. 11., Pl. VIII. The division takes place as follows: The 
chromosomes in the anaphase of the first spermatocytes arrange them¬ 
selves in a place the axis of which is at right angles to the axis of 
the spindle. Then they change their position, and order themselves in 
a plane which is at right angles to their former position (PL X., Fig. 4.). 
At the same time the centrosome also divides and the daughter centro¬ 
somes pass toward opposite poles. Concurrently forms the second matu¬ 
ration spindle the axis of which is at right angles to that of the first 
spindle. We can see on Fig. 4., PL X., that the one daughter group of 
chromosomes of the first spermatocytes already occupied the equatorial 
plate of the new second spindle, and the second group is in rearrang¬ 
ing concurrently with the formation of the spindle, while the fibres of 
the first spindle have not yet disappeared. Fig. 11., PL IX., shows a 
later stage, the late metaphase immediately before the telophase. This 
figure shows a cell having two parallel spindles which have arisen in 
the manner described above, while the division of the cell is indicated 
only by a slight incision. On. Fig. 9., PL X., four spermatids are figured, 
the reciprocal position of which indicates a similar origin. 
At an other time, as mentioned, a resting period is intercalated 
between the two divisions. The duration of this period is variable. 
Sometimes the nucleus does not transform itself, strictly speaking, into 
a resting nucleus, i. e. no nuclear membrane arises, and the chromatin 
does not form a reticulum (PL X., Fig. 3.\ but the chromosomes remain 
separated, and soon arrange themselves in the second maturation spindle 
which has arisen in the mean-time. We can sometimes observe in such 
cells even the fibres of the first spindle which fact points to a very 
short resting period. 
The first division is, however, in most cases, succeeded by a lon¬ 
ger resting pèriod, when a distinct nuclear membrane arises, i. e. the 
nucleus becomes reconstructed. The chromatin of these cells forms lar¬ 
ger masses connected by achromatic threads (PL X., Fig. 2.), in which 
chromatin granules are suspended. This stage is in some respects simi¬ 
lar to the resting stage of the spermatogonia and spermatocytes, but 
