BULLETIN OF THE UNITED STATES FISH COMMISSION. 101 



Portuguese uiollusk. Some distinguished oyster-cultuvists have, in fact, 

 held that the Portuguese oyster is liable to cross with the Ostrea edulis, 

 thus impairing the purity and diminishing the value of our indigenous 

 oyster. These persons even announced that they had observed un- 

 equivocal traces of this hybridization in the oysters coming from Arca- 

 chon. This statement caused so ranch interest among the oyster cul- 

 turists of Arcachon that one of the fishing inspectors in England urged 

 his conntrymen to buy no more oysters coming from the Arcachon Bay. 



Allow me, Mr. Minister, to lay before you the result of my observa- 

 tions on this point. Themollusk known under the name of the Portuguese 

 oyster does not belong to the same genus as our indigenous oyster. 

 While the latter ranks among the mullusks belonging to the genus 06' 

 trea, the Portuguese oyster takes place among those which compose the 

 genus Gryphee^ the species called Gryphee angulcusc {Gryplima angu- 

 lata, Lamarck). In other words, the Portuguese oyster is not an oyster 

 from a zoological point of view. To give any basis for the theory of 

 hybridization between the two mollusks, it would be first necessary to 

 prove that the zoologists have made a mistake in creating these two 

 genera, and that Lamarck was wrong in separating the gryi^hseas from 

 the oysters properly so called. Eeally, in the present state of science, it 

 is impossible to admit the crossing of two species belonging to dift'erent 

 genera. On the contrary, all that we know is opposed to the possibility 

 of such a hybridization. So that, I repeat, until it is demonstrated that 

 the genera GrypJuva should be struck out from our classifications, the 

 fact of cross-breeding between the mollusk of the Tagus and our edible 

 oyster cannot be admitted. Even admitting the generic identity of the 

 two mollusks, the characters appealed to by those who believe in their 

 hybridization do not seem to have any great scientific vahie. These 

 characters, in fact, only relate to the coloring of the shell, and no one 

 is ignorant what a variation of color there may be in animals belong- 

 ing, incontestably, to the same species. Finally, to pass nothing in 

 silence, I will add that from experiments made by MM. de Montauge 

 and Bouchon-Brandely (experiments which do not appear tome to have 

 been conducted with enough scientific precision) it would seem that the 

 spermatozoa of the Portuguese oyster cannot fertilize the eggs of 0. 

 edulis. 



I can affirm, for my part, that during my stay at Arcachon I have 

 not noticed anything which can make me believe in the deterioration 

 of tlie oyster coming from that region. 



To recapitulate, I do not believe in the crossing of the two mollusks ; 

 but I hasten to add that the introduction of the Portuguese oyster into 

 our waters does not seem to me without danger. We know that when 

 two species are placed side by side in a limited space there takes place 

 between them what an illustrious naturalist has named the struggle for 

 existence. This struggle must sooner or later terminate in the defeat, 

 the disappearance, of the weaker species. Under these conditions, the 



