6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL.98 



Common in the lagoon, particularly in the strainings from the 

 Lyngbya masses, Clipperton Island, Mexico (Schmitt 21), July 21, 

 1938. 



OOCYSTACEAE 

 Oocystis solitaria Wittrock, approaching forma major Wille 



Generally solitary, occasionally 2-8 individuals in a common mem- 

 brane, the cells to 24 ll wide, 36 ja long, broadly round-oval ; wall firm, 

 with well-defined knobs at each pole, both of the individual cells and 

 the colonial envelope when it is present. 



Frequent among filamentous algae in the lagoon, Clipperton Island. 

 Mexico (Schmitt 21), July 21, 1938. 



ULVACEAE 

 Ulva sp. 



Juvenile, only about 15 mm. tall, thickness above to 45 p., cells in 

 section a little deeper than broad. Apparently abundant. 



From rocks, shallow water along the shore of Fernandina Island, 

 Archipelago de Colon, Ecuador (Narborough Island, Galapagos Is- 

 lands) (Schmitt 23), July 25, 1938. 



OEDOGONIACEAE 

 Oedogonium sp. 



Sterile and not determinable. Filaments about 8.5 fx diameter. 

 Filaments frequent, among other algae in the lagoon, Clipperton 

 Island, Mexico (Schmitt 21), July 21, 1938. 



VALONIACEAE 



Halicystis ovalis (Lyngbye) Areschoug 



With Amphiroa annulata, from rocks, shallow water along the 

 shore of Fernandina Island, Archipelago de Colon, Ecuador (Nar- 

 borough Island, Galapagos Islands) (Schmitt 24), July 25, 1938. 



Valonia ventricosa J. Agardh 



In shallow water, probably from reefs, and bearing numerous 

 epiphytes, Old Providence Island, Colombia (Schmitt 32), August 6, 

 1938. 



