xxt. OYSTERS. 307 



T leave others to speculate ; for I am terribly sceptical 

 of our ever attaining to much knowledge of molluscan 

 psychology. 



In America they muzzle their oysters when they send 

 them to a distance. Oysters usually feed at the turn of 

 the tide, and thus contract a habit of opening their valves 

 at regular intervals. To do this when they are travelling 

 is fatal, for out runs the water and they soon die. They 

 are, therefore, muzzled to prevent their incontinently 

 yawning in this unseemly way. 



During the summer months oysters become " sick," and 

 are then out of season. But the sickness is not unto 

 death but unto life. For if a sick oyster be examined, 

 the mantle-cavity and the interspaces between the gills 

 will be found to be packed with a granular slimy substance, 

 known to fishermen as " white spat," and disclosed under 

 the microscope of the naturalist as a teeming mass of 

 developing eggs. As development proceeds, the granules 

 become coloured, and the fishermen call them " black 

 spat." Frank Buckland likens the spat in this condition 

 to very fine slate pencil dust ; and he found from ex- 

 periment that the number of developing eggs in an oyster 

 varies from 276,000 to 829,000. 



, " One fine hot day the mother-oyster opens her shell 

 and the young escape from it in a cloud, which may be 

 compared to a puff of smoke from a railway engine on a 

 still morning. Each little oyster is provided at birth with 

 swimming organs, composed of delicate cilia, and by 

 means of these the little rascal begins to play about the 

 moment he leaves his mother's shell." 



The " little rascal " in some respects resembles and in 

 other respects differs from its mother. It resembles its 

 mother in having a shell of two valves, but the valves are 

 smooth and transparent as glass ; symmetrical and united 



