[33] OYSTER-CULTURE UPON SHORES OF BRITISH CHANNEL. 705 



The following measurements, showing the increase in the dimensions 

 of oysters reared by M. Monnier, will i)rove of interest: 



An oyster, said to represent a fair average, which was spawned at 

 Auray in 1875, and was detached from the collector in January, 1876, 

 had a diameter when placed in the pare, the following April, of 2i or 3 

 centimeters. Early in September of the present year its diameter had 

 Increased to 7 centimeters 8 millimeters. Another, spawned in 1874, 

 and placed in the pare in April, 1875, measured, about the 1st of Sep- 

 tember, 1876, just 9 J centimeters. Finally, a specimen spawned in 1873 

 had acquired in September, 1876, the enormous diameter of 11 centime- 

 ters 4 millimeters. 



Like results have been obtained at the establishment of Dr. Leroux. 

 In the month of March of the present year M. Leroux transferred from 

 his pares at La Trinity some of the fry of 1875, which had been detached 

 from the collectors in January, 1876. At the period of my visit to Les 

 Sables, these oysters had attained diameters of 7 and 7^ centimeters. 



The method of treating the oyster is the same at Les Sables as else- 

 where. The manipulations are neither more nor less frequent. Care is 

 taken that they shall not become covered with mud. The pares are 

 carefully maintained in repair. The confervoid growth is removed as 

 it forms. Pla<;ing too great a number of oysters in one inclosure is 

 carefully guarded against.* In the intervals between the necessary 

 manipulations the pares are left undisturbed. 



Although the concessions at Les Sables d'Olonne are of very limited 

 extent, they raise there each year about 10,000,000 oysters, hardly one- 

 tenth of which are obtained from the dredging. It is not to be pre- 

 sumed that this is the limit of production. 



The conversion of the salt marshes adjacent to the oyster jiarcs into 

 Claires will be accomplished in a very short time. 



Isle de R:6. — In the Isle de R6 the breeding and rearing of oysters 

 is carried on to some extent, but this industry is not very important. 

 The areas suitable for the cultivation of the oyster are not extensive, 

 and moreover it is not possible to utilize the western shore of the island 

 on account of the violence of the sea, which is there called ^hner sau- 

 vageJ'^ 



Among the pares which are maintained, I will mention those of M. 

 Dupeux-Boyer. They were established about fifteen years ago in the 

 premises of an old mill. The are situated at Martray, in the face of the 

 sea ("mer smivage^^), but protected from its violence on one side by a 

 sand-dune, on the other by the Bay of Bier-d'Ars, the waters of which 

 are conducted to them by a canal. 



The concession is divided into claires averaging 50 to 60 meters in 

 length and 20 to 30 meters in width, which are separated by earthen 

 embankments from 25 to 30 centimeters high. These claires receive 

 water at everj^ tide. 



'' A clairo having an area of 150 square meters, for example, should not contain more 

 than 6,000 to 8,000 oysters. ^. -;':* T~^ . - . 



S. Mis. 46 45 X'^^-' '^ ^ X 



