BULLETIN OP TTTi: UNITED STATES EISII COMMISSION. 231 



ami .Iiuic. These oysters, inclosed in wooden boxes, llie ui)per and 

 lower i)ortion of wliicli was composed of laths abont a centimeter apart, 

 were placed in the deepest parts of the lagoon, on bottoms almost 1-J 

 meters [o feet] dee}). 



It should be stated that there was considerable mortality among the 

 oysters, but as we ascertained later this was caused by a little fisb very 

 ♦•ommon in the lagoons of tho south, of a harmless appearance, but ex- 

 ceedingly voracious, called the goby. Wherever there was any consid- 

 erable loss, both in the oyster-boxes and in th.e lish-pots, we noticed 

 these little lisli. What was particularly surprising was to see by tbe 

 side of oysters whose death might be attributed to different causes 

 others which were in good condition and evidently developing in a 

 healthy manner. A sick oyster which will finally succumb does not 

 grow. One day, when raising one of the boxes deposited in the pond 

 of Lattes, we found in it such fine, fat, and large gobies that they could 

 no longer escape from the box, owing to their size. Having evidently 

 found in this box something that was very mnch to their taste, they 

 had establislied themselves in it. But they had reached their fine con- 

 dition at the expense of our oysters, most of which were dead and half 

 of them had been devoured. Further observations have shown that 

 the goby is really a dangerous enemy to the oyster. The oyste'rs may 

 be protected against them by having the boxes covered with a close 

 net- work of metal. 



We were fortunate enough to have another proof during last season 

 of the remarkable vitality of the Portuguese oyster. In the pond of 

 La Nouvelle oysters of this variety lived several months in water con- 

 taining so little salt that the densimeter scarcely indicated the i^resence 

 of salt at all. 



In short, large portions of the ponds of Berre, Mauguio, Thau, La 

 Nouvelle, and Leucate appear i>erfLCtly adapted to the cultivatinm of 

 the Portuguese oyster. 



EXPEUIMENTS WITH COMMON OYSTERS. 



At the same time when we commenced our experiments with the arti- 

 ficial fecundation of Portuguese oysters we undertook a series of ex- 

 periments relative to the incubation, hatching of the eggs, develop- 

 ment, and fixation of the en^bryos of the common oyster. 



We shall pass as rapidly as possible the mere technical parts of cer- 

 tain questions; but to make this report clear it is necessary to give a 

 succinct account, from an embryological point of view, of the natural 

 history of the mollusk in question. 



The ordinary oyster, known as the Ostrea cdulis, is a hermaphrodite. 

 Among Prenchnien, Quatrefages, Lacaze-Duthiers, Milne-Edwards, 

 Coste, Gerbe, Davaine, and others; and among foreigners, Eyton, Mo- 



