128 



Amphora lybica, E., Lake Pontchartrain and Amite river. 

 Amphora lineolata, E., Lake Pontchartrain. 



GOMPHONEME2E. 



Gomphonema coronatum, E. — (numerous specimens) — Amite 

 river. This is a very graceful and beautiful species. 

 Gomphonema Turris, E., Amite river. 

 Gomphonema dichotomum, K., Baton Rouge. 

 Gomphonema glans, E., Baton Rouge. 

 Gomphonema constrictum (?), E. Amite river. 



NAVICULE^E. 



Navicula leptogongyla (?), E., Amite river. 



Navicula viridis, Nitzsch., Amite river. 



Navicula major (?), K., Amite river. This specimen is one of the 

 finest in the collection. Corresponds with Pritchard's figure PL vn., 

 but has no tumid centre. 



Navicula mesogongyla (?), E., Rapides. 



Navicula afiunis, E , Rapides. 



Navicula amphiofomphus, E., Rapides and Amite River. 



Navicula amphisphenia, (?) E., (specimens in great number,) West 

 Baton Rouge. This species resembles N. cuspidata. but is somewhat 

 ventricose, or rather rhombic lanceolate in outline. It has the 

 nodule elongated. It is generally perfectly smooth, but sometimes 

 a specimen is found which is closely and most finely striated. Striae 

 are perfectly perpendicular and parallel and reach the median line. 

 There are numerous specimens in front, side and oblique view. 

 When alive they are yellow and seem to be covered by a membrane, 

 having a linear, broad, transverse band in the center. Some of the 

 specimens are very large, measuring over an inch in size, others are 

 comparatively small. The valve is subacute, but any modification 

 of its lateral position renders the apices broader in proportion as it 

 approaches the front view, which is nearly linear. 

 Navicula Fusidium, E., Rapides. 

 Navicula Silicula, E., Baton Rouge. 



Navicula hemiptera, (?) E., Pontchartrain. This specimen is finely 

 striated. 



Navicula crabro, E., Pontchartrain. 



