406 BULLETIN OF THE NATURAL HISTORY SOCIETY. 
than in the southern waters. Biddulphia is comparatively 
rare in the north, as is also Campylodiscus , though several species 
of both genera occur. On the other hand Synedra undulata ( .= 
Toxarium undulatum Bail) found at Richibucto and Dalhousie, 
has not yet been observed in the Bay of Fundy, though reported 
by Dr. Mackay as occurring at Canso and common around 
the shores of Prince Edward Island. Synedra longissima, 
Biddulphia rhombus , Caloneis Schuminiana, Campylodiscus 
Ralfsii and C. Hodgsonii , Syndendrium diadema , Dickiea pinnata , 
Meridion circulare , with many Naviculae, Coscindisci and 
Nitschias, found on the North Shore, have not yet been noted 
in *the waters of the southern coast. 
Another point of interest on the North Shore is the com- 
mingling of fresh water and salt water types. In a previous 
Bulletin of this Society (No. XXVII) this subject was well 
illustrated, it being pointed out that both upon the St. Croix 
River and the St. John, with its tributary, the Kennebecasis, 
typical marine forms are to be found at a distance of fifteen 
or twenty miles from the sea, while forms usually regarded as 
of fresh water origin occur in the harbor of St. John. The 
same commingling is noticeable upon the North Shore, but it 
is seen in the occurrence of fresh water species in waters that 
are decidedly salt rather than the reverse. Thus Pinnularia 
viridis, Synedra ulna , Stauroneis phoenic enter on, Surirella elegans 
and S. spenldida , all typical fresh water forms, occur, not infre- 
quently, in the salt waters of Miramichi River at Newcastle 
and Chatham. There are not, however, upon the North Shore 
such powerful river and tidal currents as in the lower St. John, 
and falls or dams frequently mark a point, above which, of 
course, marine forms cannot enter, though fresh water swarms 
from above may be swept outward. 
The comparative absence of distinctively plankton forms 
in the waters bathing the northern coasts as compared with 
their abundance and variety in the waters of the Bay of Fundy 
is also worthy of notice, though this may be due to the fact that 
the collections herein alluded to were nearly all littoral, con- 
sisting mainly of muds from shallow waters, washed from eel- 
