620 OYSTERS, AND ALL ABOUT THEM. 



metres from the river, and the district of Verdon, and 

 receives the water when the tides are at their highest. 



It is composed of several compartments varying in 

 depth, and communicating by means of broad incisions in 

 the platform separating them. The entire surface would 

 exceed a hectare. At new and full moon the flood-gate 

 for alimentation is opened, so that the fish brought dowri 

 by the current may enter, and the water be renewed. 

 This process is repeated several times during spring tide. 

 Owing to the situation of these marshes on the open 

 shores of the Gironde, the water is never stagnant even at 

 the times of quadrature ; the sea swell, and the winds from 

 the ocean and from the river, keep the water perpetually 

 aerated by agitating its surface. 



The marsh selected by us was of a depth of from five 

 to six feet in the centre, and from two to three feet at the 

 sides. Some stakes placed at intervals supported pieces of 

 tile suspended in the water by wires. 



From the commencement of July to the end of August 

 M. Gassiau, Instituteur at Verdon, who throughout our 

 campaign seconded us with an intelligence, zeal, and 

 devotedness worthy of all praise, was careful to turn in 

 several times a week the result of the fecundation, which 

 he managed himself with rare ability and remarkable cer- 

 tainty. Three hundred oysters only were devoted to these 

 experiments. 



On the 8th August he visited the collectors, and 

 observed on all, without exception, some hundreds of little 

 oysters of from one to two millimetres. Each of these suc- 

 cessive fecundations was visible by the presence of objects 

 whose size indicated their age. Having had the curiosity 

 to know in what number they were to be found, we counted 



