386 The Ohio Naturalist. [Vol. IX, No. 1, 



enlarged centrosome or blepharoplast is of exactly the same 

 nature as the centrosonies at the spindle poles in the earlier 

 divisions. In the antheridial cells of Marchantia, therefore, we 

 have normal centrosonies appearing at each division from the 

 very earliest stages through the great grandmother, grand- 

 mother and mother cell stages preceding the formation of the 

 spermatozoids and according to Van Hook the}" are also present 

 in the vegetative cells. 



The lack of prominent asters in the last division is no doubt 

 due to the decrease in size of the cell with corresponding decrease 

 in the amount of cytoplasm. There is not sufficient space or 

 material in which an aster could be developed. 



It is needless to give further observations, for they would 

 only be a repetition of the observations so thoroughly reported 

 by Ikeno. In conclusion it is only necessary to repeat that 

 anyone with proper perseverance may obtain preparations which 

 will verify the results here given; and further it is evident that 

 the blepharoplast of Marchantia is only a slightly modified 

 centrosome which can be traced back through many cell gen- 

 erations and which is probably present in all the cell divisions of 

 the entire ontogeny. 



This studv was completed at the Botanical Garden of the 

 University of Zurich, and I desire here to express my thanks to 

 the director, Professor Dr. Hans Schinz, for many favors shown 

 me while working in his laboratory. 



LITERATURE. 



Ikeno, S. Die Spermatogenese von Marchantia polv- 

 morpha. Beih. z. Bot. Centralbl. 15: 65-8S, 1903. 



Ikeno, S. La formation des antherozoides chez les Hepa- 

 tiques. Comptes Rendus de I'Acad. des Sci. 136: (328-629, 1903. 



Ikeno, S. Blepharoplasten im Pflanzenreich. Biol. Centralbl. 

 24: 211-221. 1904. 



MiYAKE, K. On the Centrosome of Hepaticeae. Bot. Mag. 

 19: 98-101. 1905. 



Van Hook, J. M. Notes on the Division of the Cell and 

 Nucleus in Liverworts. Bot. Gaz. 30: 394-399. 1900. 



Ikeno, S. Are the Centrosomes in the Antheridial Cells of 

 Marchantia polymorpha Imaginarv? Bot. Mag. 19: 111-113. 

 1905. 



Escoyez, E. Blepharoplaste et centrosome dans le March- 

 antia polymorpha. La Cellule 24: 247-250, 1907. 



Schottlander, p. Beitrage zur Kenntniss des Zellkems und 

 der Sexualzellen bei Kryptogamen. Cohn's Bcitr. zur Biol, der 

 Pflanzen 6: 267-304. 1892. 



Belajeff, W. Ueber die Centrosome in den spermatogenen 

 Zellen. Ber. d. Deutsch. Bot. Gesells. 17: 199-205. 1899. 



