121) 



Navicula didynia, E., Poutchartrain. 



Navicula dicephala, E., Rapides. 



Navicula tabellaria, E., Rapides. 



Navicula cuspidata, K., Rapides. 



Navicula ainphirhynchus, Baton Rouge. 



Navicula rhyneocephala (?) Fr. Differs from the figure in Pritch- 

 ard by tapering more gradually to the rostrate apices, and stria- 

 only partially visible. 



There are a great number of Navicular undetermined. 



Stauroneis Pkcenicentron, E., Rapides. 



Stauroneis platystoma (?), E., Amite river. 



Stauroneis semen, E., Lake Pontchartrain. 



There are many fine specimens of Stauroneis undetermined. 



Pleurosigma obtusatum, Sulliv, Baton Rouge. 



Pleurosigma attenuatum, K., Lake Pontchartrain. 



Pleurosigma curvulum, E., Baton Rouge. 



Algm Marine — Fucacw. 



Sargassum vulgare, Aq., Beach of Grand Isle. 



The Alga3 proper, called " Seaweeds/' are rare on the Louisiana 

 Gulf coast, for there are no rocks to which they can attach them- 

 selves. We have several specimens of the class of Confervse and 

 Ulvaceae, but they are not determined. 



