6l8 OYSTERS, AND ALL ABOUT THEM. 



At the outlet, an apparatus consisting of a wall of fine 

 sand, faced with boards to stem the ripple of the sea, 

 allowed the water to run out, but prevented the embryos 

 from escaping with it. The lower claire alone was used in 

 the experiments. The upper one, in which when possible 

 the water was stored, served as a filtering bed, and thus the 

 conduit of alimentation admitted into the claire for experi- 

 ment only such water as had already been clarified. 



Having taken these first steps, the product of the arti- 

 ficial fecundation obtained by different methods was ad- 

 mitted into the reservoir. 



This took place in the second week of June. 



As we expected, it was possible to find spat on the 

 collectors at the end of that month, or the commencement 

 of July. M. Tripota, who had soon mastered the manipu- 

 lations, and in our absence supplied our place, continued 

 to introduce into the claire ova which had been fecundated, 

 and moving larvae. 



The term assigned for the duration of the trial having 

 expired, the collectors were examined, but showed, appa- 

 rently, no trace of reproduction. It had been a deception. 

 But the reflection that the spawning season had not yet 

 commenced in the Gironde allowed us to hope for ultimate 

 operations of a happier nature. The claire was emptied, 

 modifications were made in the supply of water, and a fresh 

 effort was made in daily introducing the combined ele- 

 ments of generation. 



On the 24th July an inspection was made of the tiles ; 

 on this occasion they .were all found with spat on them. 

 It was then perceived that the former experiments had not 

 been so fruitless as we had supposed. In fact, to each of 

 the tiles immerged quite at the first were attached from 

 twenty to thirty young oysters, measuring about a centi- 



