5o8 



The Ohio Naturalist. 



[Vol. IX, No. 7, 



interchange of the granular chromatin and the individual shape 

 (probably dependent on the linin structure) still be retained. 

 The chromatin granules appear to become diffused and spread 

 out no less than the linin, to be massed together again at definite 

 stages in the ontogeny. 



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All the figures are from accurate Abbe camera lucida drawings on the 

 same scale. Fig. 1. Spirem of second cleavage just at the time of the 

 separation of the chromosomes. The spirem is already broken at one 

 point. The position of the two long and two short chromosomes is clearly 

 marked, showing that the chromosomes are not yet paired. Figs. 2-9. 

 Pole views of equatorial plates of first and second cleavage. 



Then again it is even possible, with all of our present knowl- 

 edge, that the chromatin acts as a unit organism and produces 

 periodically a definite number of chromo.somes of rather definite 

 size and form without localizing any given quantity of the sub- 

 stance in any definite part. There is no need to insist that a 

 viscid plasm must comport itself like a set of wooden blocks as 

 some would have us believe. However, I think that most of the 

 evidence so far presented points to a material individuality of 

 the linin groundwork of the chromosome. 



