KARYOKINETIC FIGURES OF CENTKIFUGED EGGS. 113 



relatively rare, but the disarrangement may be much more con- 

 siderable than in the case illustrated (Fig. 7). The ends of the 

 spindle may be much spread out and the chromosomes may be 

 turned around at right angles to their ndrmal orientation. 



B. The effect of the introduction of basophile granules into the 

 area of the karyokinetic figure is, however, entirely different. 

 They cause no disarrangement, but appear to become oriented 

 like the rays of the aster, or the fibers of the spindle. The evi- 





m&, 



f^ft-.-.' ., /&$. 



ibvK:^; . " 



FIG. 7. Section of an egg of Chcetopterus centrifuged 2,300 revolutions in 7 



seconds at a. radius of 13 cm. Killed in Flemming's fluid. The figure represents 



the centripetal half of the egg. Fat granules have entered the spindle and destroyed 

 part of its structure. 



dence for this conclusion is based on the behavior of the dense 

 aggregation of the basophile granules found in the central end of 

 the inner dense zone after the action of low centrifugal powers, 

 i. e. t of the basophile cap (Figs. 2, $8, and 4/>). 



The heavy stain of the basophile cap lies entirely in the gran- 

 ules, not at all in the ground substance. It is true that the 

 ground substance between the granules appears darker in the 

 basophile cap than elsewhere, but this is an effect due to the light 

 passing through basophile granules at a lower focus. In thin 

 sections it is not evident at all. The conclusion is really proved 

 by the fact that such an effect is seen only in the basophile cap, 

 and that this may lie in any part of the wall of the dense zone, 

 depending on the direction of action of the centrifugal force. 



i. Let us note first that the granules that compose the baso- 

 phile cap have a uniform distribution when remote from the 



