SEXUAL REPRODUCTION OF THALLOFPHYTES. 307 
This at first sight may seem surprising. Zoospores, how- 
ever, are masses of protoplasm whose conjugation has many 
important features of resemblance to the formation of plas- 
modia. The cell-wall of zoospores is feebly developed, or at 
any rate offers but little valid resistance to the fusion of two 
individuals. ‘The spores of the Myzxomycetes set free their 
protoplasm as uniciliate zoospores which gradually lose their 
characteristic form and become amceboid. The ameebe being 
destitute of any cell-membrane readily run together in a 
kind of wholesale conjugation and produce a plasmodium— 
a kind of compound zygospore, which eventually passes into 
a resting state and by processes more or less complicated 
developes the spores. 
CuytTRIDIE®.—In the 4th edition of his ‘ Lehrbuch,’ p. 
256, Sachs suggests the propriety of placing this group in 
juxtaposition with the Mywomycetes, as it would be probably 
found that the zoospores conjugate. This has been actually 
found to be the case by Sorokin! in a form described by him 
as Tetrachytrium. Chytridiee may occupy an intermediate 
position between Myxomycetes and Saprolegniea.? 
PRoTOMYCES is a parasitic fungus of obscure affinity. It 
produces sporangia which discharge with considerable force 
their contained spores. These conjugate in pairs to form a 
zy gospore.® 
Fre. 5.—Closterium striolutum. A, before; B, after; C, in conjugation 
(after Ralfs). 
* See ‘Quart. Journ. Mic. Sci.,? 1874, p- 298. 
2 See Sachs, ‘ Traité de Bot.,’ traduit par Van Tiegh 899 
3 See De Bary, ‘ Beitr. z. Morph. d. Pilze, Tift. ae em, p. 002. 
