THE LARVA AND SPAT OF THE CANADIAN 

 OYSTEB 



J. STAFFORD, M.A., Ph.D. 



I. The Larva 



In the summer of 1904, at Malpeque, Prince Edward 

 Island, on behalf of the Canadian Marine Biological Sta- 

 tion, I undertook to gather what information I could upon 

 the life of the oyster from the time it becomes a distinct 

 bivalve veliger to the time when it is recognizable by 

 every oyster fisherman as a spat oyster. 



Brooks, of Johns Hopkins University, Baltimore, to 

 whom belongs the immortal, glory of having discovered 

 that American oysters are unisexual and that artificial 

 fertilization of the eggs and rearing of the larvae are 

 possible, had worked out the spawning, fertilization, 

 segmentation, gastrulation and organization up to the 

 earliest microscopic free-swimming bivalve veliger, and 

 there was no lack of literature on oyster culture begin- 

 ning with macroscopic oyster spat of, let us say, the size 

 of one's thumb-nail. But the intermediate stages, 

 mostly microscopic, seemed to be scarcely, if at all, known, 

 and there were many questions as to the time and place 

 where they might be found as well as to their anatomy 

 and comparison with other genera which required in- 

 vestigation. 



The possibility of raising young oysters from eggs and 

 keeping them alive without admixture with other indi- 

 viduals or other species until one had seen the whole 

 series of continuous transformations into the adult 

 seemed next to impossible. I chose rather to learn to 

 recognize the larval oyster in plankton collections, a 

 method which had apparently received no attention. I 



