19 



C. parasitica Thuret. 



Queens : Jamaica Bay, Pike. Suffolk : Greenport, Pike. 

 C. pulvinata ( Mert. ) Ag. 



Suffolk : Greenport, Pike. 

 C. scopulorum (Web. & Mohr) Ag. 



Suffolk : Greenport, Pike. Queens : Cold Spring Harbor, 

 Johnson. 



RIVULARIA Roth. 

 R. atra Roth. 



Kings : Hell Gate, Flushing, Pike. Queens : Cold Spring Har- 

 bor, Johnson. 

 R. nitida Ag. 



Queens: Jamaica Bay, Pike. 



ISACTIS Thuret. 



I. plana (Harv. ) Thuret. 



Kings : Fort Hamilton, Pike. Queens : Jamaica Bay, Pike. 



BACILLARIALES. 



DIATOMACBAE. ' 

 MELOSIRA Ag. 

 M. Borrerii Grev. 



Kings : Bay Ridge. 

 M. granulata (Ehrb. ) Ralfs. 



Frequent throughout the island. Fossil at Cold Spring. 

 M. nummuloides (Bory) Ag. 



Kings: Bay Ridge. 

 M. sulcata (Ehrb.) Kiitz. 



Queens: Arverne, Edwards. 



M. varians Ag. 



Kings: Prospect Park, Brooklyn Water Supply. 



HYALODISCUS Ehr. 

 H. Franklinii Ehr. 



Queens: Arverne, Edwards. 

 H. stelliger Bailey. 



Queens: Arverne, Edwards. 

 i Pyxidicula compressa Bail. ) 



Arverne, Edwards. 



CYCLOTELLA Kiitz. 

 C striata (Kiitz.) Grun. 



Queens: Arverne, Edwards. 



1 In this citation of the specie.'; Schiitts' classification in Engler and Prantl's system 

 is followed for the sake of general conformity although we prefer Van Heurck's 

 arrangement in A Treatise on the Diatomaceae. 



