[5] OYSTER CULTURE IN FRANCE. 729 



On examination of these figures it will be seen : 



1. That the number of thejmrcs, which in 1865 was only 297, amounted 

 in 1880 to 4,259. 



2. That during that period the number of oysters exported rose from 

 10,584,000 to 195,477,375, representing a value of 4,254,465 francs. 



3. That from 1870 to 1880 the number of oysters exported has ex- 

 ceeded one milliard, and it must be remarked that the oysters cannot 

 be sold until they have obtained a minimum diameter of five centi- 

 meters. 



It will be seen that the average price per thousand has greatly di- 

 minished of late years. This is due to the great quantity of Portuguese 

 oysters introduced now into the basin of Arcachon. And here I must 

 not pass over in silence the sensation which has been caused in the ostri- 

 cultural world in consequence of the introduction into our waters of 

 Portuguese mollusca. 



Some distinguished oyster-culturists have, in fact, advanced the 

 opinion that the Portuguese oyster might cross with the Ostrea edulis, 

 and by altering its purity diminish the value of our indigenous oyster. 

 They even announced that they had observed unequivocal traces of this 

 hybridization upon oysters coming from Arcachon. 



Among the cultivators at Arcachon this announcement caused an 

 emotion all the more lively as one of the inspectors of fisheries in Eng- 

 land had induced his countrymen to purchase no more oysters coming 

 from Arcachon. 



The mollusk known under the name of the Portuguese oyster does not 

 belong to the same genus as our indigeuous oyster. While the latter is 

 included in the mollusca belonging to the genus Ostrea, the former takes 

 its place among those constituting the genus Gryphcva, the species Gry- 

 yima angulata Lauuirck. In other Avords, the Portuguese oyster is not 

 an oyster in a zoological point of view. 



To aflbrd some base for the allegation of hybridization between the two 

 mollusca, it would be necessary, in the first place, to prove that zoolo- 

 gists have been mistaken in creating these two genera, and that La- 

 marck was in error in separating the GryphceafTom the oysters pro])erly 

 so called. In fact, in the present state of science, it is impossible to 

 admit the crossing of two species belonging to different genera. All that 

 we know, on the contrary, is opposed to the possibility of such a hybrid- 

 ization. 



I repeat, then, until it has been proved that the genus Gryphwa should 

 be omitted from our classifications, the cross between the mollusk of the 

 Tagus and our edible oyster cannot be admitted. 



Even allowing the identity of genus of the two mollusks, the charac- 

 ters mentioned by the partisans of hybridization do not appear to me to 

 possess much scientific value. 



These characters consist merely in the color of the shell, and no one 

 can be ignorant of the extent to which the colors may vary of animals 



