SEXUAL REPRODUCTION OF THALLOPHYTES., 313 
ment placing near the Fucacee the Alge resembling them in 
habit, such as Macrocystis, Laminaria, Sargassum, &c.; of 
these the zoospores and antherozoids are known, but the 
female organs have not been discovered. 
Ca LosLast#.—This group includes alge and fungi in 
which the protoplasm is continuous throughout the vegeta- 
tive organs of the plants, and is not divided into cells. Ap- 
proximately it may be said to include the Siphophycee on the 
one end, and Sorokin’s Siphomycetes (excluding the Mucorint, 
and possibly the Chytridine) on the other. 
Amongst the Siphophycee we know little of the repro- 
duction of any genus except Vaucheria. 
The antheridia and oogonia of this genus were discovered, 
and their functions correctly apprehended, by Vaucher 
(1803)'. But Pringsheim first put their meaning entirely 
beyond doubt in 1855 by observing the actual process of fer- 
tilization (fig. 10).2. In Bryopsis Pringsheim * believes he 
C 
Fic. 10.—Fertilization of Vaucheria sessilis. A, antheridium (a) and 
oogonium (4) before fertilization; B, antheridium (a) emitting anthero- 
zoids (¢), the cilia of which are visible (72) when they come to rest; C, 
oogonium (4) containing fertilized oosphere (oospore) surrounded with a 
cell-wall (after Pringsheim), 
1 «list. des Conf. d’eaux douces,’ p. 17. 
> “Berlin. Monatsb.,’ 1855, pp. 133-165. 
3 Thid., 1871, pp. 240-255. 
