€ANADIAX FISBERIES EXPEDTTIOX, J91.'rlo 495 



ment is arrested; in the gulf of St. Lawrence, the development can liardly be supposed 

 to begin before early May, and at the close of this month the rise of temperature in 

 the surface layers of the coastal water is distinctly apparent. On the other hand, the 

 summer temperature is not sufficiently high to favour the development of a rich 

 Ceratium plankton answering to the European plankton community called by Cleve 

 the " Triposplankton." 



More than this we can hardly say on the basis of the present observations; they 

 represent a first commencement. As a necessary foundation for further studies, we 

 must first have observations carried out throughout the entire year from a number of 

 selected stations, so that we can obtain a clear view of the annual periodicity. In this 

 connection, it will be of great interest to have investigations similar in plan to 

 the present ones, repeated over a wider area at various seasons, but a continuous 

 investigation series covering the whole of the year should first be made, in order that 

 it may be possible to choose, for the more extensive investigations, the seasons at 

 which the most imix)rtant plankton communities are in course of development. Even 

 now we may say that it would be particularly interesting to have quantitative; investi- 

 gations of the plankton in the gulf of St. Lawrence and environs for the beginning 

 of May, so that we could determine the distribution of the rich spring plankton; the 

 investigations should preferably be combined with determinations of oxygen content 

 according to Winkler's method, as this would enable us to gauge the quantities of 

 organic matter produced by the phytoplankton during this rich period of development. 



I have not considered it necessary at the present stage to give a list of the species 

 found and their synonyms. It will here suffice to refer to " Xordisches Plankton,'* 

 where the great majority of the species are described; to my paper on the plankton 

 production of the Xorth European waters in May, 1912^; and to Caroline Leegard's 

 work published at the same time (Untersuchungen ueber einige Planktoneiliateu des 

 Meeres." Kristiania, 1915. Nyt Magazin for Naturbidenskaberne, Bd. .j-j), with a 

 description of the Lahoea species and some related forms. 



3 Joe. at. 



6551—37 



