viii PREFACE. 



Micrasterias foliacea, Bail^y-^alss. Desm. 210. Worden's Pond, Ehode Island, Bailey. 



Micrasterias Bayleyi, Ralps. Desm. 211. Rhode Island, Bailey. 



Euaslrum oblongum, Ralps. Des. 80. Rhode Island, Bailey. 



Euastrum crassum, Kijtz.-Ralfs. Des. 81. Rhode Island, Bailey. 



Euastrum ansatum, Ehrh.-Ralfs. Des. 85. E. binale Kntz. Providence. 



Euastrum elegans, KuTZ.rRALFS. Des. 89. Providence. 



Euastrum binale, Rales. Desm. 91. Providence. 



Cosmarium cucumis, Corda.-Ralfs. Desm. 93. United States, Bailey. 



Gosmarium bioculatum, Ralfs. Des. 95. Providence. 



Cosmarium Meneghinii, Breb. -Ralfs. Des. 96. United States, Bailey. 



Cosmarium crenatum,, Ralfs. Des. 96. Providence. 



Gosmarium amoenum, Breb. -Ralfs. Des. 102. Providence. 



Gosmarium ornatum, Ralfs. Des. 104. Providence. 



Cosmarium connatum, Breb. -Ralfs. Des. 108. Providence. 



Gosmarium Gucurbita, Ralfs. Des. 109. Providence, 



Gosmarium grandituberculatum, Olney, n. s. ; " near C. cucumis, but with large tubercles on tho 

 frond." Providence. 



Staurastrum orbiculare, Ralfs. Des. 125. Providence. 



Staurastrum hirsutuvi, Ralfs. Des. 127. Providence. 



Staurastruvi Eystrix, Ralfs. Des. 128. Providence. 



Staurastrum gracile, Ralfs. Des. 136. Providence. 



Staurastrum tetracerum, Ralfs. Des. 137. United States, Bailey. 



Staurastrum cyrtocerum, Breb. -Ralfs. Des. 139. Providence. 



Tetmemoras Bribissoni, Ralfs. Des. 145. Providence. 



Tetmemoras granulatus, Ralfs. Des. 146. Providence. 



Peniwrn wargrari'toceMm, Brbb.-Ralfs. Des. ( GZosferwm Ehr.) Providence. 

 Pemwm Z)^'g'^'<^^s, Breb. -Ralfs. Des. 151. {Closterium lamellosum.) 

 Docidium nodulosum, Breb.-Ralfs. Des. 155. Maine to Virginia, Bailey. 

 Docidium Baculum, Breb.-Ralfs. Des. 158. United States. Bailey. 

 Docidium nodosum, Bailey-Ralfs. Des. 218. United States, Bailey. 

 Docidium constrictum, Bailey-Ralfs Des. 218 Worden's Pond, Bailey. 

 Docidium verrucosum, Bailey-Ralfs. Des. 218. Rhode Island, Bailey. 

 Docidium verticillatum, Bailey-Ralps. Des. 218. Worden's Pond, Bailey. 



Closterium Lunula, Ehrh.-Ralfs. Des. 163. New Englan-d, Bailey. 



Closterium moniliferum, Ehrh.-Ralfs. Des. 163. New England, Bailey. 

 Closteriiem striolatum, Ehrh.-Ralfs. Des. 173. New England, Bailey. 

 Closterium cuspidatum, Bailey-Ralfs. Des. 219. Worden's Pond, Bailey. 

 Pediastrum tetras, Ralfs. Des. 182. New England, Bailey. 

 Pediastrum heptactis, Ralfs. Des. 183. Providence. 



Pediastrum Boryanum, Menegh.-Ralps. Des. 187. Maine to Mexico, Bailey. 

 Pediastrum ellipticum, Hass. -Ralfs. Des. 188. Maine to Virginia, Bailey 

 Scenedesmus quadricauda, Breb.-Ralfs. Des. 190. Maine to Virginia, Bailey. 

 Scenedesmus obtusus, Meyen.-Ralfs. Des. 193. Maine to Virginia, Bailey. 



