Section IV., 1915 [141] Trans. R.S.C. 



Diatoms from the Eastern Coasts of Vancouver Island, B. C, Canada. 

 By L. W. Bailey, LL.D., and A. H. MacKay, LL.D. 



(Read May Meeting, 1915). 



So far as known to the writers no observations relating to the 

 Diatoms of the Pacific Coast of Canada have as yet been pubHshed. 

 Yet, considering the wonderfully rich Diatom flora which characterises 

 the waters of California and Oregon, and especially those of Puget 

 Sound, it may well be believed that the micro-organisms which dis- 

 tinguish the coasts of British Columbia may be equally rich and 

 varied. 



The observations which follow relate to a very small part of the 

 coast in question, viz.: to the vicinity of Nanaimo, the seat of the 

 British Columbia Biological Station, together with a number of the 

 small islands in and about Departure Bay. The collections were 

 made by members of the Biological staff and were kindly placed at our 

 disposal by Dr. C. MacLean Fraser, Director of the station, and Pro- 

 fessor McMurrich. They consist in part of plankton forms obtained 

 by the use of fine silken tow nets, in part of material scraped or washed 

 from the surface of Zostera and other coastal Algae, and partly of 

 soundings or harbor muds. No absolute separation can be made be- 

 tween these three groups, but each has distinctive features of its own, 

 and each differs from the others alike in the mode of collection and in 

 the subsequent treatment. It is therefore proposed, as far as possible, 

 to consider them separately. 



I. Plankton Diatoms. 



The Plankton, as seen upon removal from the tow nets, presents 

 the appearance of a flocculent precipitate, the colour of which varies 

 from nearly white to pale yellowish or greenish, and of which the 

 different portions cling together with great tenacity. In many in- 

 stances these features are due to the preponderance of long horned, 

 chained or filamentous forms such as Chaetoceros, Thalassiosira, Skele- 

 tonema, Melosira or Biddulphia. Mingled with these, though usually 

 in much less numbers, are such circular forms as Coscinodiscus, 

 Actinocyclus, A ctinopty chus, and Cyclotella; or ovoid forms like Surir ella 

 and Cocconeis. 



In the preparation of plankton material for examination it is 

 often sufficient to merely remove from the water the contained salt 



