Hyatt.] ^"~ 58 [March 5, 



is not an untested discovery, and it appears to us to be shown 

 more or less in all the types of the animal kingdom except the 

 Protozoa, which we have not as yet studied with the view of 

 finding examples of its action. 



Dr. Mark in his work on the Maturation etc. of the Egg in Limax 

 campestris (Bull. Mus. Comp. Zool. vol. vi, No. 12, pt. 2), gives 

 considerable attention to the bisexual theory. He also thinks 

 that the formation of the globules is not connected with sexual 

 phenomena at all, but belongs to the processes of agamic cell 

 segmentation as stated by Hertwig, and others, and lately by H. 

 W. Conn, and therefore differs radically from the casting off or 

 resorption of nuclear parts after fecundation in Protozoa. 



Fleming declares, without reserve, his belief in the homologous 

 nature of all the transformations of the nuclei and cell division in 

 the cells of plants, animals, and in ova (Beitr. z. Kenntn. d. Zelle 

 etc., Archiv. Mik. Anat. 1882), while Strassburger (ueber Theil. 

 d. Zelle p. 584 in the same periodical), admits more variability in 

 in the transformations of the nuclei, but describes only two 

 modes of division, the indirect and direct, which he considers as 

 not radically differing but correllative processes, one pathological 

 and the other the healthy normal mode. These general results 

 confirm the position formerly taken by Biitschli of the homo- 

 logous nature of these transformations throughout the animal 

 kingdom, though Fleming considers it necessary to deny that 

 they have necessarily any genetic significiance. 



That the processes of nuclear division may be incomplete 

 stages in the formation of cells may, therefore, be provisionally 

 assumed ; and the conclusion that a purely sexual result in the 

 Protozoa may become either partly or wholly agamic in the 

 Metazoa seems to us from our experience in other departments 

 of research, as we have said above, to be a natural and even a 

 probable result. That the globules may be cells thrown off in 

 some forms, and in others become merely swollen prominences of 

 the ovum which are not cast off and possibly resorbed into the 

 vitellus, or in others purely useless nuclear parts which are 

 resorbed, appear to show stages of differentiation in the same 

 process of cell division, which sometimes results in the formation 

 of separate cells and at other times is abortive. 



Biitschli has shown that spermatozoa are probably products 



