TRANSPLANTING ATLANTIC OYSTERS TO THE PACIFIC 127 



cells; that they can spawn, and that the eggs develop into active free- 

 swimming young. 



Plankton taken on every occasion at Hammond and Nanoose bays 

 had not yielded any oyster larvae, which became explainable upon making 

 the preceding observations of the reproductive organs. It was still a 

 little too early in the season. On the 25th I obtained a second lot from 

 Nanoose bay of which the forty-seventh was the first to yield eggs, all 

 the previous ones having spawned with the exception of four or five con- 

 taining sperms. The interval between the two visits had been the hottest 

 of the summer and the oysters had nearly all spawned in this period— 

 slightly later than is usual in the Atlantic. 



On the 27th I made a trip to Ladysmith (Oyster harbour) about fifteen 

 miles from the station, where I had good fortune in finding a trace of the 

 few remaining transplanted oysters. These are near to Mr. Page's house. 

 I examined several individuals and took plankton, which for the first time 

 contained larvae of the Atlantic species. They were recognizable by their 

 familiar shape and proportions, but did not present such a deep pink 

 or brown colour as in the native home of the Prince Edward Island oyster. 

 A selected specimen with characteristic postero-dorsal high umbos, large 

 convex left valve and small flatter right valve, velum, foot, pigment- 

 spot, etc., measured (Oc. V, obj. 4) 42 long by 37 high (=.289 x .255 mm.) 



The only remaining bit of evidence desirable to prove that the Atlantic 

 oyster can breed successfully in the Pacific, and that its brood can grow 

 up into healthy oysters, would be to find stages of its spat from the smal- 

 lest possible up to the size of the transplanted eastern oysters. It was of 

 course too early for the present year's spat, and I did not have much time 

 to look for those of a previous year. This was the sixth summer from the 

 date of the transplanting and some of the oysters may have been mature 

 four or five years. The amount and character of the new growth of shell 

 (on one of two specimens could be made out six additions in growth) sug- 

 gested that it may have taken some time for them to become acclimatized 

 or accommodated to the new conditions, so that it is not likely that any 

 of their progeny had attained to a size larger than the accompanying 

 native Pacific oysters. It is reasonable to suppose that the comparatively 

 few descendants of the two and a half barrels planted in Hammond bay, 

 five barrels in Nanoose bay, and one barrel in Oyster harbour, when dis- 

 persed over the broad areas at their disposal, and reduced by the usual 

 combinations of circumstances, and especially in the presence of thousands 

 of British Columbia oysters of varying sizes, shapes, and complexions, 

 would not prove at all conspicuous objects. It is likely that young spats 

 of the two species are not easily distinguishable from the exterior. With- 

 out this information, the facts of maturity, spawning, fertilization, em- 

 bryonic and larval development, previously referred to, are conclusive. 



