284 Ma rquette, Manifestations of polarity in plant cells vrhich usw. 
metamorphosis of the spermatid. Whether they also play a role 
analogous to that of tlie central bodies during nnclear diyision is 
perhaps still an open question. Webber conclnded 1 ) that the 
blepharoplast takes no part in nnclear diyision and that it is not 
the homologue of the centrosome, a conclnsion wbich Strasburger 2 ) 
also reached after reviewing the evidence at band at the time. 
Hirase 3 ) and Ikeno 4 ) on the other hand considered the blepharo¬ 
plast the homologue of the centrosome althougli they present no 
very conyincing eyidence of its participation in nuclear diyision. 
On the other hand, Belajeff 5 ) in his observations on the micro- 
gametophytes of Marsilia traces the blepharoplast through a number 
of cell generations preceding the antherozoids and finds that they 
divide preparatory to nuclear diyision and that the spindle figure 
develops about the separating halyes just as about the central 
bodies in animal cells. This account of Belajeff’s is the most 
complete we haye describing a participation of the blepharoplast 
in nuclear diyision. It is to be hoped that further inyestigation 
will tlirow more light on the origin of the blepharoplast and its 
possible relations to the spindle, both in the vascular cryptogams 
and in the Cycads. 
While the multipolar stage in spindle development lias been 
found to be of wide spread nccurrence it appears that its multi¬ 
polar polyarch origin, to employ Strasburger’s terminology, is 
restricted in general to sporogenous tissues; that in vegetative 
cells the spindle is diarch from the beginning. Rosen 6 ) gave an 
essentially correct sketch of spindle development in jegatative 
cells, but it is especially due to Nemec’s work 7 ) that attention 
has been called to the diferences between the mitoses in vegetative 
and in sporogenous tissues. Strasburger 8 ) has however pointed 
out a series of intermediate types wliich indicate that there is no 
such great disparity in the methods of spindle formation in sporo¬ 
genous and yegetative tissues as Nein ec at first maintained. 
As far as the central bodies are concerned they are no more 
in evidence in those cells in which the spindle is diarch from the 
beginning of its appearance than in the sporogenous cells where 
the spindle has a polyarch origin, so that at present the view is 
] ) Webber, H. J.: Notes on the fecundation of Zamia and the pollen- 
tube apparatus of Ginkgo. (Bot. Gaz. Vol. XXIY. 1897. p. 232.) Spermatogenesis 
and fecundation of Zamia. 1. c. p. 77. 
2 ) Strasburger, E.: Hist. Beitr. VI p. 185, 1900. 
3 ) Hirase: Jour. Coli. Sei. Imp. Univ. Vol. XII p. 103. 
4 ) Ikeno: Jahrb. f../wiss. Bot. Bd. 32 p. 571. 
5 ) Belajeff, W.: Über die Centrosome in den spermatogenen Zellen. 
(Ber. d. Deut. bot. Ges. ßd. XVIII. p. 199.) 
6 ) Bosen, E.: Beiträge zur Kenntnis der Pflanzenzellen. (Cohn J s Beitr. z. 
Biol. d. Pflanzen. Bd.jVIL 1895. p. 225.) 
7 ) Nernec, B.: Über die Ausbildung der achromatischen Kernteilungs¬ 
figur im vegetativen und Eortpflanzungsgewebe der höheren Pflanzen. (Bot. 
Ctblt. LXXIV. 1898. p. 1.) Zur Physiologie der Kern- und Zellteilung. (Bot. 
Ctblt. LXXVII. 1899. p. 241.) Über die karyokinetische Kernteilung in der 
Wurzelspitze von Allium cepa. (Jahrb. f. wiss. Bot. Bd. XXXHI. 1899. p. 313.) 
8 ) Strasburger, E.: Hist. Beitr. VI p. 118, 1900. 
