140 AMPHIMIXIS OR ESSENTIAL MEANING OF [XII. 



the process is the same as in other cases ; for the mature 

 germ-cells contain only half the number of idants which are 

 normally found in the species. 



Henking interprets his corresponding observations upon the 

 development of the ova, in the following manner : — The first 

 division of the mother-cell is the ' reducing division' suggested 

 by me, for this alone reduces the idants to half their normal 

 number : the second division is that which I have called the 

 ' equal division,' i. e. the means by which a number of ids, equal 

 to that present before this division commences, passes into each 

 daughter-nucleus ; and this is rendered possible because the 

 longitudinal splitting of the idants depends upon a doubling 

 of the ids by division. 



If this explanation be valid, the interpretation offered above 

 of the doubling of the idants in the mother-cells oiAscaris must 

 fail, and I doubt whether anj?- other feasible explanation is to be 

 found. Henking attempts to reconcile the discrepancy between 

 the two observations by altogether doubting the doubling of the 

 nuclear rods oiAscaris. I have, however, convinced myself, by 

 an examination of the preparations of my pupil, Herr Arnold 

 Spuler, that the doubling cannot be denied. Furthermore, it 

 was this very process which first afforded an explanation of 

 the double division of the mother-cells. Why then should 

 there be this universal double division of which we are so com- 

 pletely assured by the general occurrence of the two polar 

 bodies of the ovum ? Regarding spermatogenesis only, we 

 might perhaps be inclined to be satisfied with the answer that 

 the number of sperm-cells must be four times that of the 

 mother-cells. But, as I have indicated above, the mere increase 

 of the spermatozoa might be brought about, and to any extent, 

 by additional division of the original sperm-cells; and when 

 we remember that the mother-cell of the ovum undergoes this 

 double division, whereby three out of the four daughter-cells 

 simply disappear as polar bodies, it becomes clear that the 

 process is controlled by some deeper necessity. And if any- 

 one doubts this, and is inclined to think, with Lameere and 

 Boveri, that the polar bodies are merely a phyletic reminis- 

 cence, he should remember that rudimentary organs and pro- 

 cesses always tend to vary, and that it is inconceivable that, in 

 all sexually reproduced Metazoa, these two nuclear divisions 



