4 COMMISSION OF CONSERVATION 



workers at home and contemporaries abroad. His works have ever since 

 been regarded as standard on those parts of the subject dealt with, and 

 have been extensively copied, with little inclination to either verify or 

 extend them. 



Occasion of the Present Work. — In Canada, the study of the Atlantic 

 oyster began when our movable Biological Station, in the fifth year 

 of its existence (1903), became located at Malpeque, P.E.I., the most 

 important centre of our oyster fisheries. There was assembled the 

 largest staff of investigators ever present at one time at the station, 

 and to each was apportioned his part in the schedule of research. My 

 own part seemed to promise little and had to do with the more 

 mechanical work of boating, collecting, experimenting, and, inci- 

 dentalh^, of continuing the study of faunas previously carried on at St. 

 Andrews, N.B., and Canso, N.S. During the first summer a good deal 

 was learned about the local physical environment, form-variations, habits, 

 food, bacteria, associates, and such like things connected with the life of 

 adult oysters; but nothing of importance was accomplished in connection 

 with the embryology. Some attempt was made with a view to determine 

 the period of ripening of the eggs, and to artificially fertilize them, as 

 well as to procure young spat, but these attempts did not furnish even a 

 local orientation with regard to the problems of development. 



My own connection with these problems began with the succeeding 

 summer (1904), when I was requested to do what I could in the remaining 

 short season of our stay at Malpeque, for it was understood that the station 

 would be removed beyond oyster areas for the following year's work. Not 

 to have had active experience during the preceding summer, nor to 

 have read the special literature relative to these problems, was a dis- 

 advantage which for a time kept me very much in the dark. Naturally 

 I began by applying my knowledge of faunas — macroscopic adult animals, 

 and microscopic adults and young, and the various methods of procuring 

 them. I already knew almost every species of bivalve that could be ob- 

 tained between tide-marks, or brought up by a naturalist's dredge between 

 low-water mark and fifty fathoms depth, and I had collected myriads of 

 bivalve larvae in plankton nets. Besides, I had learned to recognize the 

 oldest stages of the free-swimming larva of the mussel {Mytilus edulis L.), 

 by comparing the bivalve larvae of plankton collections with minute 

 mussels found attached to rockweed (Fucus) at St. Andrews, and I 

 thought a similar method might be turned to account in determining other 

 larvae, perhaps that of the oyster. Accordingly I turned all my energy 

 for a time towards the collecting and scrutinizing of bivalve larvae in the 

 plankton. At first they all looked pretty much alike, excepting that 

 some were comparatively large and others small; but, after a diligent study 

 of collections from various parts of Richmond bay, it appeared that some 

 were brownish or yellowish, while others were gray, pale and transparent, 



