17 



Illustrated Species 



A total of lo^t- species are illustrated, representing **3 of 

 the common genera found at the Water Pollution Surveillance System 

 stations. Some of the species were selected primarily to demonstrate 

 the morphological diversity within the genera. The figures have 

 been selected from a number of publications (p. 18) and the figure 

 credits are referred to by number immediately following the species 

 names. The cell dimensions given are generally those from the 

 figure source, but in some cases these have been supplemented with 

 our own observations. The geographical distribution of 96 of the 

 species is shown in the accompanying chart (p. 100), taken from 

 "Plankton Population Dynamics", by L. G. Williams, PK3 Pub. No. 

 663, Suppl. 2, 1962. Additional information regarding diatom 

 distribution can be found in the WP3S Annual Compilations of Data, 

 1960-61, 1961-62, and 1962-63, PHS Pub. No. 663. 



