274 J. E. S. MOOBE. 



In a former essay, while discussing the meaning of the differ- 

 ence in the component parts of the spheres apparent in the 

 works of Flemming, Hermann, van Beneden, Boveri, and 

 others, I remarked, " Comparison between the spheres and 

 their constituent parts in various animals might appear pedan- 

 tic, and, in the present state of our knowledge, unnecessary, if 

 it were not that some of these parts are probably, as we have 

 seen, the fleeting expression of metamorphic phenomena; while 

 others (such as the central body), though dividing, retain their 

 characteristics unimpaired; " and I have ventured to repeat 

 this as showing that the great pioneers of this phase of cytology 

 had already hunted the all-important part of the sphere down 

 to the narrow limits of the centrosome. And the fact that in 

 Branchipus six or eight bodies indistinguishable from one 

 another exist at first, and that these afterwards fuse to aug- 

 ment the size of the two actually chosen to occupy the spindle 

 apices, does not prevent anyone from regarding these two of the 

 six or eight, as endowed with special properties if he pleases, 

 nor does their relation to the interglobular spaces affect the 

 point in any way that I can see. Whether two of these bodies 

 are really to be regarded as difl*erent from the rest is a point on 

 which at present I ojffer no opinion. 



Comparison with the Ovigenesis. 



It will be seen that the spermatogenesis of Branchipus 

 corresponds in the main with that described by vom Bath in 

 Gryllotalpa, and that the reticulum has disappeared in the 

 ultimate division altogether (fig. 16). Now if, as I have shown, 

 there is reason to believe the reticulum in this particular in- 

 stance is a mechanical factor in portions of the karyokinesis, 

 all possibility of such phenomena will come to an end with the 

 complete fusion of the clear globules, and there is thus a 

 definite reason why the subdivision goes thus far and no farther, 

 at any rate for a time. 



In the ovigenesis proper — that is, in the metamorphosis 

 among those cells which directly produce the eggs— there is 

 nothing special ; but among the cells subsidiary to this process. 



