Notes on a New Boveria species. i 1 



giving rise to four chromosomes of about equal length (fig. 11, c 

 and d). These chromosomes arrange themselves in equatorial parts 

 of the spindle, all disposed parallel to one another and to the 

 spindle axis. In tliis position each of them splits longitudinally, 

 thus giving rise to eight slender chromosomes (fig. 11, e). After 

 that, half the number of the chromosomes — that is to say, four of 

 them — travel to cither pole of the spindle (fig. 11, ,/'). A set of 

 fine diverging fibres, extending from the poles into the interior of 

 the spindle, is visible in properly manipulated prep u-ations. Wq 

 have not detected in the neighbourhood of the poles any structure 

 -which may be construed to represent the centrosome. The entire 

 spindle now stretches out extensively ; its middle parts gradually 

 thin out, until it is there cut off into two, thus brhiging the first 

 division of the synkarion to an end. 



Each of the two daughter synkarions soon afterwards enters 



into a resting or reconstruction period (fig. 12, a). During this 



Pjg J 2. period the chromosomes disintegrate 



^ ^ into separate granules, which are ag- 



rrt 



"^ ^ / gregated together not very densely in 

 ^^ ^ aÈ 1^! f\ Ci) the central parts of the now spherical 

 ^"^ daughter synkarion. This state seems 



to last only for a short time. Tlien, the chromatin granucles are 

 loosened and rearrange themselves into an entangled spireme-like 

 band (fig. 12, b). This band becomes discontinuous at three 

 places, and by condensation brings forth four longish and relative- 

 ly thick chromosomes lying parallel to one another (fig. 12, c). 

 Now the daughter synkarions are each transformed into a spindle 

 figure (fig. 12, d) similar to that of the first synkarion division. 

 The spindle gradually elongates, in the sequel becoming constricted 

 in the middle. In this second division of the synkarion the 

 chromosomes do not perform longitudinal sphtting, as they did m 



