DIATOMS OF NEW BRUNSWICK. 
407 
grass ( Zostera ) or the piles of' wharves and bridges, while in 
only a few instances were plankton nets employed. Of the 
five genera — - Chaetoceros , Skeletonema, Rhizosolenia, Thalas- 
siosira and Asterionella — -usually regarded as distinctively 
planktonic — only three have been observed and these hot in 
large numbers. Chaetoceros decipiens Cleve; and Rhizosolenia 
setigera Bright; were found at several localities, (the latter 
especially about Bathurst Harbor, Shippegan and Lemeque) 
and Skeletonema in one instance only (at Benjamin River), 
but Nitschia longissima , which, with its long processes, is well 
adapted for flotation, is quite common, especially in collections 
from Bathurst and Dalhousie. Biddulphia Mohilensis Bail, 
found in Bathurst Harbor, is also usually regarded as a planktonic 
form, as are the several species of Coscinodiscus. 
