OYSTER CULTURE IN FRANCE. 591 



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 hybridation. 



Until then, I repeat, it has been proved that the genus 

 gryph&a should be omitted from our classifications, the 

 cross between the mollusc of the Tagus and our edible 

 oyster cannot be admitted. 



Even allowing: the identity of ffenus of the two 



o * 



molluscs, the characters mentioned by the partizans of 

 hybridation do not appear to me to possess much scientific 

 value. 



These characters consist merely in the colour of the 

 shell, and no one can be ignorant of the extent to which 

 the colours may vary of animals belonging unquestion- 

 ably to the same species. Finally, to be silent on no point, 

 I will add that, from the experiments of MM. de Montauge 

 and Bouchon-Brandely (experiments which do not seem 

 to me to have been conducted with sufficient scientific 

 precision), it would appear that the spermatozoa of the 

 Portuguese oyster cannot fecundate the ova of the ostrea 

 edulis. 



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

 Arcachon I never observed any fact which would make me 

 believe in a change in the oyster produced in that district. 



To sum up, I do not believe in a cross between the 

 two molluscs ; but I must add that the introduction into 

 our waters of the Portuguese oyster does not strike me as 

 unattended with danger. 



It is known, in fact, that when two species are com- 

 pelled to live side by side in a limited space there springs 



