MUSEUM OF COMPARATIVE ZOOLOGY. 335 



selnden amoeboiden Gestaltabweichungen (Strahlensonnen von Pseudo- 

 podien)." (p. 177.) 



The inaccuracy of his conceptions of the nature of the " Strahlen- 

 sonnen " is too apparent to need a special refutation. To consider these 

 astral figures, which belong primarily to the protoplasm of the yolk, as 

 pseudopodia of the nucleus^ is to ignore the evidence of most careful 

 observers ; to claim that the nucleus is capable of automatic change of 

 form, is quite another thing, to which I cannot object. How far Brandt 

 is misled by the observations of others appears (p. 1 78) from the view 

 held by him that the membrane of the germinative vesicle becomes the 

 spindle of Biitschli, while its active substance escapes from the membra- 

 nous enclosure at two opposite points. (!) The unreliableness of Brandt's 

 conclusion, that the nuclear reticulum is only a pseudopodal extension of 

 the nucleolus, and that the granules occurring in it are only local thick- 

 enings of the pseudopodia, has, I believe, been shown by the recent 

 exquisite researches of Flemming and others. 



Repiachofp ('78) gives rather unsatisfactory figures of the condi- 

 tion of the nucleus during cell division. Before each segmentation 

 it becomes homogeneous, and the beginning of its division antedates 

 that of the cell. In Figs. 10-12 the author reproduces the stages 

 of nuclear division, showing the " dumb-bell " with a slender handle. 

 More or less prominent asters, centring in the homogeneously stained 

 heads of the dumb-bell, are figured. The heads are designated as 

 "Theilstiicke des Furchungskernes." Neither spindle fibres nor thick- 

 enings seem to have been observed, nor yet the incipient stages of 

 nuclear formation, if, as is reasonable to suppose, this takes place in 

 the manner now known to prevail with the eggs of most animals. 



The fourth chapter of the summary on fecundation, segmentation, 

 etc., given by Von Jhering ('78„ pp. 143-156), is devoted to the 

 phenomena of segmentation and cell-division. It does not lie within 

 the aim of his paper to contribute new material to the discussion. 



Besides the method of cell increase which Auerbach denominates 

 palingenetic, and which may safely be said to be the most wide spread of 

 all forms. Von Jhering recognizes as different from it the free cell-forma- 

 tion of the botanists, and the equivalent methods in the segmentation 

 of insect eggs and in the division of epithelial cells. As claimed by 

 Strasburger, this latter method njay be related to the former, in the 

 sense that it is produced by a shortening of the process of development. 

 A simple genuine division (i. e. without metamorphosis of the nucleus), 

 from which budding is in no way fundamentally different, cannot be 



