110 PROCEEDINGS OF THE AMERICAN ACADEMY. 



similar phenomenon in the male germ cells of Scolopendra, where the 

 spindle remnants of both the first and the second spermatocyte 

 divisions are eliminated during a rotation of one daughter cell upon 

 the other. 



It seems possible, therefore, that this globule, composed principally 

 of the substance of the interzonal filaments, is not comparable with the 

 spermatocyte of ordinary spermatogenesis, and therefore not with a 

 polar body in ovogenesis. 



The smaller of the two bodies resulting from the real mitosis which 

 follows the elimination of the interzonal body bears a striking resem- 

 blance, it must be admitted, to the polar cell of eggs, and it is un- 

 questionably the result of a true, though modified, cell division. 

 This phenomtnon seems, however, never to have been seen in the 

 spermatogenesis of any other animal. There is here an equal division 

 of chromatin accompanied by a very unequal division of the cytoplasm, 

 precisely as in the formation of the polar cell in eggs. The small cell 

 apparently begins to undergo a metamorphosis parallel to that of its 

 larger sister cell, as Meves has maintained. Although Meves believes 

 that the small cell eventually degenerates, positive evidence of this 

 has not yet been produced. If it is to be interpreted as the homo- 

 logue of a polar cell, the question at once arises. Which of the two 

 polar cells usually produced does it represent 1 From the standpoint 

 of Meves, the first body might be looked upon as a partially abortive 

 attempt to produce the equivalent of the first polar cell, and the 

 second body might then be regarded as in some sense the equivalent 

 of the second polar cell ; but even were his view about the first (inter- 

 zonal) body correct, the division of nuclear substance accomplished by 

 the formation of the second bud would more strongly point to this, 

 rather than the first, as being the homologue of the first polar cell. 

 That view is, perhaps, strengthened by the facts here presented, which 

 tend to show that the body first produced has nothing whatever to do 

 with cell division, and that in the occasional doubling of the centro- 

 some (Figures 10, 11) some progress is made toward a second cell 

 division, which, if completed, would result in the formation of either 

 two spermatids or a second true polar cell. However, it must be 

 admitted that, on the assumption that the interzonal body has nothing 

 to do with an attempted cell division, the peculiar changes passed 

 through by the chromatin preceding and during the period of the 

 elimination of that body remain unexplained and without a parallel. 



On the other hand, the beginning metamorphosis of the small 

 nucleated body (second bud) suggests that it is the equivalent of a 

 spermatid rather than a spermatocyte of the first order, and this view 



