Cell-Division in Sporangia and Asci 
BY 
R. A. HARPER, 
Professor of Botany in the University of Wisconsin. 
With Plates XXIV-XXVI. 
HE most thoroughly studied case of spore-formation 
-L in sporangia is that of Saprolegnia and Achlya. Here 
the slenderness and transparency of the objects made 
accurate observation of the processes taking place in the 
dividing protoplasm possible, without the employment of 
any very refined technique. The behaviour of the nuclei 
has not been sufficiently investigated in this case, but the 
observations of Humphrey 1 , Trow 2 , and others leave little 
doubt as to the main facts. The sporangium, when cut off 
from the parent hypha, is multinucleate, and the ultimately 
formed zoospores are probably uninucleate. In the light 
of Belajeff’s 3 observations on the formation of the cilia in 
antherozoids, it would be extremely interesting to determine 
1 Saprolegniaceae of the U.S., Trans. Am. Phil. Soc. Vol. xvii, 1892-3. 
2 The Karyology of Saprolegnia, Ann. of Bot. ix, 1895, p. 609. 
3 Uberdie Cilienbildner in den spermatogenen Zellen, Ber.d. D. Bot. Gesellschaft. 
Bd. xvi, p. 140, 1898. 
[Annals of Botany, Vol. XIII. No. LII. December, 1899.] 
