MICROSCOPICAL OBSERVATIONS. 



27 



NORTHERN LOCALITY, NEAR PROVIDENCE, R. I. 



For the sake of comparison with the above lists of Southern forms, I give here 

 the names of the species noticed by me in Wainskut Pond, near Providence, 

 R. L, on the 18th of July, 1850. 



Desmidie^. 

 Ankistrodesmus falcatus, Corda. 

 Arthrodesmus convergens, Ehr. 

 Cosmarium ovale, Ralfs. 



" undulatum, Corda. 



Closterium Dianae, Ehr. 



" angustatum, Kg. 



" lineatum, Ehr. 



" Jenneri, Ralfs. 



" moniliferum, Ehr. 



Docidium nodulosum, Breb. 

 Desmidium Swartzii, Ag. 



" quadrangulatum, Ralfs. 



Didymoprium Borreri, Ralfs. 

 Euastrum ansatum, Ehr. 



" circulare, Hass. 



" didelta, Ralfs. 



" elegaiis, Breb. 



" gemmatum. Kg. 



" oblongum, Ralfs. 



" rostratum, Ralfs. 



" veri'ucosum, Ehr. 



Hyalotheca dissiliens, Breb. 

 Micrasterias pinnatifida, Kg. 



" truncata, Breb. 



" denticiilata, Breb. 



" rotata, Ralfs. 



Penium digitus, Breb. 



" margaritaceum, Breb. 

 Pediastrum pertusum, Kg. 



" boryanum, Menegh. 



" ellipticum, Hass. 



" heptactis, Menegh, 



" tetras, Ralfs. 



" selenaea, Kg. 



Dbsmidie^, 

 Scenedesmus obliquus, Kg. 



" obtusus, Meyen. 



" qnadrieauda, Breb. 



Sphserozosma excavatum, Ralfs. 

 Staurastrum alternans,' Breb. 



" gracile, Ralfs. 



" hirsutum, Ehr. 



Spirotcenia condensata, Breb. 

 Tetmemorus Brebissonii, Ralfs. 

 Xanthidium fasoiculatum, Ehn 



D1ATOMAOE.S. 

 *Diatoma stellaris, B. 

 Eunotia serra, Ehr. 

 Himantidium arcus, Ehr. 

 Gomphonema acuminata, Ehr. 

 Tabellaria flocoulosa, Ehr. 

 . " fenestrata, Ehr. 



Infusoeia. 

 Arcella vulgaris, Ehr. 

 Brachionus Bakeri, Ehr. 

 Coleps hirtus, Ehr. 

 Difflugia proteiformis, Ehr. 



" spiralis, B. 

 Dinobiyon sertularia, Ehr. 

 Euglena viridis, Ehr. 



" pleuroneetes, Ehr. 

 Floseularia ornata, Ehr. 

 Melicerta ringens, Sehr. 

 Peridinium cinctum, Ehr. 

 Rotifer macrourus, Ehr. 



" vulgaris, Ehr. 

 Stentor polymorphus, Ehr. . . 1 _^ 



See also in the Appendix a list of forms found near Sal'^*^ r.i „.:.»., oy I'jiomas 

 Cole, Esq. .y' ^j- ' 



By consulting the above Usfes^the snrcies found at each locality will be seen. 

 The following tables will siVo^^' rhe same in a more condensed form, and will 

 also exhibit the geographical distribution of species. 



