THE AMERICAN MIDLAND NATURALIST. 



Synedra undulata (Bailey) — C. J. Fish. 



Thalassiothrix frauenfeldii (Grun) — C. J. Fish, H. B. Bigelow. 



Thalassiothrix longissima (Cleve and Grun) — C. J. Fish and 



H. B. Bigelow. 

 Thalassiothrix nitzschioides (Grun) — C. J. Fish and H. B. 



Bigelow. 



NAVICULOIDEAE. 



Nitzschia closterium (Smith) — C. J. Fish. 

 Nitzschia longissima (Breb.) Ralfs — C. J. Fish. 

 Nitzschia paxillifer (0. F. Mueller) Heiberg — C. J. Fish. 

 Nitzschia seriata (Cleve) — H. B. Bigelow and C. J. Fish. 



SOLENIOIDEAE. 



Corethron valdiviae (Karstan) — C. J. Fish. 

 Guinardia sp. — H. B. Bigelow. 

 Guinardia flaccida (Castr.) — C. J. Fish. 

 Leptocylindrus danicus (Cleve) — C. J. Fish. 

 Rhizoselenia alata (Brightw.) — H. B. Bigelow. 

 Rhizoselenia alata f. genuina (Gran) — C. J. Fish. 

 Rhizoselenia alata f. gracillima (Cleve) — C. J. Fish. 

 Rhizoselenia calcar-avis (Schultze) — H. B. Bigelow. 

 Rhizoselenia delicatula (Cleve) — H. B. Bigelow. 

 Rhizoselenia faeroeensis (Ostf.) — H. B. Bigelow. 

 Rhizoselenia hebetata var. semispina (Hensen) — H.B.Bigelow. 

 Rhizoselenia obtusa (Henson) — H. B. Bigelow. 

 Rhizoselenia setigera (Brightw.) — H. B. Bigelow. 

 Rhizoselenia shrubsolei (Cleve) — H. B. Bigelow. 

 Rhizoselenia styliformis (Brightw.) — H. B. Bigelow. 



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