BULLETIN OF THE UNITED STATES FISH COMMISSION. 227 



brycs iiom about one linndicd eggs treated. Less than a month hiter 

 all these oysters had spawned. 



Another observation was made at Toulon. It was our good fortune 

 to have as our (;o-worker M. Senes, the principal administrative agent 

 of marine, whose ability in nuitters relating to oyster culture is univers- 

 ally acknowledged. In the course of the m6uth of July, when the 

 scorching heat on the shores of the Mediterranean was most intense, 

 IM. Senes received from Verdon breeders which, when shipped, were 

 ascertained to be fully capable of exercising the generative functions, 

 and which, immediately upon their arrival, Avere placed at the most 

 favorable points in the roadstead of Toulon. All the efforts made by 

 M. Senes and myself to have the eggs hatched were in vain. Fission 

 set in, and the eggs reached an advanced stage of development, but 

 the process was not completed. This state of infecuudity lasted during 

 the months of July and xYugust, and in some cases continued till the 

 middle of September, and in a few even till the beginning of October. 

 Not till then did M. Senes obtain lively embrj'os. 



Other oysters which had for some time been accustomed to the waters 

 of the roadstead exhibited nearly the same phenomena. Although we 

 ascertained as early as July that the generative elements were ou the 

 l)(»int of arriving at maturity, the tendency toward reproduction did not 

 manifest itself in these specimens in a manner which promised results 

 till the month of October, that is to say, almost three months later.* 



We should add that most of the time fecundation did not succeed as 

 well at Cette as at Verdon during the hot season, because in the latter 

 place the precaution was taken to use only cooler water, and because 

 the elements were brought together in receivers large enough to prevent 

 the effect of the surrounding atmosi)here from being felt too quickly. 

 It was also necessary to change the water several times during the course 

 of incubation. Subsequent researches have shown that the incuba- 

 tion of the eggs and the development of the embryos in water whose 

 temperature exceeds 32° C. [89.0° Fahr.] can hardly be accomplished. 

 Is this also the case with the American oysters and the unisexual 

 oysters of the Indian Ocean? We hope soon to hear this question 

 answered. 



After stating that the experiments made at the island of Aix, in the 

 moats of the fortifications, whose water is not sufficiently renewed and 

 not at all aerated, were seriously interfered with by the stormy weather 

 and the excessive heat, and yielded fewer results than we had antici- 

 pated, considering the successful manner in which fecundation had been 

 accomplished, we give below a brief report on experiments made at the 

 mouth of the Loire, at Pouliguen, in the oyster-cultural establishments 



* We must here state that the opinion expressed iu our last year's report as regards 

 the infecundity of Portuijncse oysters penned in Mediterranean waters is contradicted 

 by this observation. 



