PLANKTON OF THE GULF OF MAINE 
419 
I may add, for the sake of completeness, that much the same list of diatoms 
occurred over the whole breadth of the continental shelf off Shelburne, Nova Scotia, 
on March 19, 1920 (stations 20073 to 20076), though here the variety of species per 
Fig. 116. — Occurrence of certain neritic diatoms in February and March, 1920, a dot for each locality record of the following 
species: Biddulphia aurita, Chsetoceras debile, Ch. contortum, Ch.diadema, Ch. didymum, Ch.laciniosum, Ch.mitra, Ch. 
sociale, Eucampia, Lauderia glacialis, Licnophora, Skeletonema, Thalassiothrix nitschioides, and Thalassiosira. The 
hatched curve incloses the area where most of the stations yielded five or more of these species; the stippled curve where 
we found none of them 
station averaged larger than in the neighboring parts of the Gulf of Maine, as, for 
example, in Browns Bank, in the Northern Channel, and along western Nova 
Scotia. The most interesting feature of the diatom communities along this line is 
