1240 OYSTERS, AND ALL ABOUT THEM. 



I have elsewhere stated that the development of the 

 American and the Portuguese oyster is very similar to that 

 of the oslrea edulis, except that there is no period of incu- 

 bation within the mantle cavity of the parent in these two 

 species. Hence it is that so-called artificial fertilisation 

 is possible, that is to say, that fertilisation may be allowed 

 to take place in a tank or aquarium in which the conditions 

 are under control. But if it is possible to procure a supply 

 of spat from the American oyster by the swarms of larvae 

 in confinement ; it ought to be possible in the case of the 

 European oyster. All that would be necessary would be 

 to take a number of mature oysters containing white spat 

 and lay them down in the tanks until the larvae escape. 

 This would be simply carrying oyster culture a step further 

 back, and instead of collecting the newly-fixed, to obtain 

 the free larvae in numbers and so insure a fall of spat 

 independently of the uncertainty of natural conditions. 



In nature the beds are liable to variations, and though 

 Professor Huxley is rather sceptical on this subject, it 

 seems that they are easily brought into an unproductive 

 condition by overdredging. 



Touching upon this point, I am sure that 1 cannot do 

 better than to lav before the intelligent reader the distin- 



^ O 



guished Professor's views upon this important matter, in 

 his own words. 



There can be no doubt that the great mass of oysters 

 in an oyster bed may be removed by systematic and con- 

 tinuous dredging. But those who are best acquainted 

 practically with the nature of that operation will be least 

 inclined to believe that all the oysters on a bed could be 

 cleared off in this way, even if the attempt were made ; 

 and, as it must cease to be profitable to dredge long before 

 the point of entire clearance is reached, it is plain that, in 



