404 
BULLETIN OF THE NATURAL HISTORY SOCIETY. 
examined, indicating that most of these prevail along this entire 
sea board. Of the species found at nearly all the localities the 
following may be mentioned. 
Grammatophora marina; Melosira varians and M. nummu- 
loides ; Navicula viridis ; N. ovalis; Actinoptychus undulatus; 
Cocconeis scntellum ; Coscinodiscus radiatus ; Epithemia turgida; 
Synedra ulna ; Surirella ovalis ; Biddulphia aurita ; Coscinodiscus 
eccentricus ; Homoecladia sigmoidea; Hyalodiscus subtilis; 
Nits chia sigmoidea ; N. vermicular is; Pleuro sigma Balticum. 
While those which are very rare or found only at one or two 
points include: 
Synedra undulata ( Toxarium undulatum Bail); Eunotia 
diodon and E. tetraodon ; Grammatophora stricta; Himantidium 
bidens; Navicula mesolepta and N. elegans; Nitschia circumsuta 
and N. closterium ; Raphoneis amphiceros; Caloneis Schuminiana; 
Amphora ovalis and A . costata; Bacillaria paradoxa; Biddulphia 
rhombus and B. Mobilensis ; Cyclotella striata and S. compta; 
Campylodiscus spiralis; Encyonema coespitosum, Rhoicosphenia 
curvata , Dickiea pinnata {?); Colletonema subcoherens ; 
Rhoicosphenia curvata ; Syndendrium diadema ; Skeletonema 
costatum (?) 
Of species of which only one or two specimens have been 
observed the following may be mentioned: 
Campylodiscus Hodgsonii; C. Ralfsii; Climacosphenia curvata; 
Auliscus sculptus ; Triceratium sp(?); Mastogloia exigua ; 
Stauroneis acuta; Stauroneis aspera; Plagiogramma. 
The association of certain species at particular points in 
great numbers,, sometimes to the almost complete exclusion of 
everything else, may be noticed here. Thus in the channel 
of the harbor of Richibucto Rhabdonema occurs in great 
numbers, accompanied by sessile clusters of Cocconeis scutellum, 
sometimes embracing a hundred or more individuals, while in 
that of Bathurst Acnanthes longipes is equally noticeable, accom- 
panied, though to a lesser extent, by Grammatophora marina. 
The abundance of Diatoms in this latter harbor is beyond con- 
ception, it being only necessary to drag a plankton net through 
a few yards of water in the flats between the bridges to have 
