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Annals New York Academy of Sciences 



lorica whether it is a Chrysophycean, Craspedomonadina, or even one of the 

 colorless flagellates of the Bicoeca group. 



Cysts 



The same problem will arise for the Chrysophyceae cysts. We will have, at 

 all times with the present forms, siliceous cysts with their pore and plug. But 



Figure 9. Cysts of Uroglena (after Bourrelly). 1: Uroglena americana; 2: U. Conradi 

 var. gallica; 3: U. botrys; 4: V. Nygaardii; 5: U. volvox var. uplandica; 6: U. volvox; 7: U. 

 soniaca; 8: U. Lindii;9: IL marina; 10: IL europaea; 11: U. notabilis. 



Figure 10. Cysts of Chrysaslrella furcala (Chr\sostomataceae): polymorphism (after 

 Bourrelly). 



within the same genus, the cysts have a highly varied ornamentation, and the 

 identity of forms in the cysts does not seem at all related to the organism. The 

 endogenous cyst is built within the cell, around the nucleus (figure 8). The 

 cytoplasmic parts left out of the cyst contribute to the external ornamentation 

 of the cyst wall. The cyst is siliceous, but as was the case with the Diatomae, 

 a pectic substance remains bound to the silica. The plug which closes the 

 pore of the cyst is itself siliceous, but with a substantial pectic tendency. 



