Marquette, Manifestations of polarity in plant cells vvhich usw. 283 
pollen-mother-cells of Larix 1 ) it is to be noted that a large nurnber 
of them come no nearer to presenting* a developmental history of 
the spindle figure carefully worked out on tecbnically adequate 
preparations tlian did the earlier centrosome studies on plant cells. 
Tliere liave also appeared since tlie „Bonner Studien“ a 
large number of papers in which granul es or aggregations of 
granules are described as lying at the spindle poles in various 
species of higher plants and considered as of the nature of centro- 
somes. 2 ) The same criticism applies to all of these latter investi- 
gations — the content tliemselves too much witli the finding of 
a granule or granules at the spindle poles during one or several 
stages of mitosis without tracing the development of these granules 
and their relation to the formation of the spindle. That liowever 
the mere occasional finding of a granule at the poles of the com- 
pleted spindle or in any other isolated stage of mitosis shows 
nothing as to the function or nature of that granule has been 
repeatedly shown. 
From the standpoint of our knowledge of the so-called blepharo- 
plast. tlie question of tlie existence of central bodies in the higher 
plants assumes a somewhat different aspect. It has been shown 
by Belajeff, 3 ) Shaw, 4 ) and others that blepharoplasts occur quite 
generally among the vascular cryptogams, and the work of Hirase, 5 ) 
Ikeno, 6 ) and Webber 7 ) lias given us full data as to their presence 
and structure in the lower Gymnosperms. They appear as well 
defined Organs of the cell although present, as far as known, 
■fiuring but a limited number of cell generations. In their function 
as ciliaforming Organs, the blepharoplasts show a behavior ana- 
logous to that of the central bodies of animal cells during tlie 
1 ) Allen, 0. E.: The early stages of spindle-formation in the pollen- 
mother-celle of Larix. (Ann. Bot. Yol. XYU. 1903. p. 281.) 
2 ) See for instance Bernard, Quelques remarques a propos des centres 
kinetiques. (Jour, de Bot. XIX. 1905. p. 80.) who also gives an extensive list 
of works belonging in this category. 
3 ) Bel aj eff, W.: Über den Xebenkern in spermatogenen Zellen und die 
Spermatogenese bei den Farnkräutern. (Ber. d. Deut. bot. Ges. Bd. XV. 
p. 337.) Über die Spermatogenese bei den Schachtelhalmen. (Ibid. Bd. XVII. 
p. 399.) Über die Ähnlichkeit einiger Erscheinungen in der Spermatogenese 
bei Tieren und Pflanzen. (Ibid. p. 342.) Über die Cilienbildner in den sper¬ 
matogenen Zellen. (Ibid.. Bd. XVIII. p. 140.) 
4 ) Shaw, W. R .: Über die Blepharoplasten bei Onoclea und Marsilia. 
{Ber. cl. Deut. bot. Ges. Bd. XVI. 1898. p. 177.) 
5 ) Hirase, S.: Xotes on the attraction-spheres in the pollen-cells of 
Ginkgo Biloba. (Bot. Mag. Tokyo. Yol. YIII. 1894. p. 359); Etudes sur la 
fecundation et Fembryogenie du Ginkgo biloba. Jour. Coli. Sei. Imp. Univ. 
Tokyo. Vol. YIII. Pt. II. 1895. p. 307): Etudes sur la fecondation et Fembryo¬ 
genie du Ginkgo biloba. (Ibid. Vol. XII. Pt. II. 1898. p. 103.) 
6 ) Ikeno, S.: Zur Kenntnis des sogenannten „centrosomähnlichen^ Körpers 
im Pollenschlauch der Cycadeen. (Flora. Bd. 85. 1898. p. 15.) Untersuchungen 
über die Entwicklung der Geschlechtsorgane und den Vorgang der Befruchtung 
bePCycas revoluta. (Jahrb. f. wiss. Bot. Bd. 32. 1898. p. 557.) Also Jour. Coli. 
Sei. Imp. Univ. Tokyo Yol. XII p. 152. 
7 ) AVebber,. H. J.: Pecifiiar structures occuring in the pollen tube of 
Zamia. (Bot. Gaz. Yol. XXIII. 1897. p. 453.) Spermatogenesis and fecundation 
of Zamia. (Bur. Plant Ind. Bull. Xo. 2. 1901. U. S. Dept. Agri.) 
