BIRTH, GROWTH AND REPRODUCTION OF OYSTERS, icy 



cunningly opens its shells and waits awhile. If there is 

 the slightest jar or shake in the water, snap go the shells 

 in an instant, like a steel trap on the leg of a rabbit. All 

 being again quiet, suddenly the parent oyster ejects the 

 spat in a dense cloud, spreading it out in all directions 

 like a jet of steam from a stationary locomotive on a calm 

 day. In a minute or two afterwards out comes another 

 cloud of spat from the oyster, and so on till the perform- 

 ance is concluded." 



" If a glass vessel is filled from the stratum of surface 

 water in which the larvae swim, and held up to the light, it 

 will appear full of minute particles only ^th of an inch 

 long, and therefore just visible to the naked eye which 

 are in active motion. An ordinary hand magnifier is 

 sufficient to show that these minute organisms have very 

 much the aspect of the Rofifera, or ' wheel animalcules,' 

 so common in fresh water. They have a glassy transpa- 

 rency, and are colourless, except for one or more dark 

 brown patches ; while, at one end, there is a disk, like the 

 'wheel' of the Rotifers, the margins of which are appa- 

 rently in rapid motion, and which serve as the organs of 

 propulsion. When this propeller is moderately active, the 

 larvae dance up and down in the water, with the disk 

 uppermost ; but when the action is more rapid, they swim 

 horizontally with the disk forward." (_/") 



From the observations I have made, I am convinced 

 that in the embryonic state young oysters are very suscep- 

 tible of cold. If the temperature of the sea suddenly drops 

 many degrees, they all close their shells, and fall to the 

 bottom dead, just as a frosty night will " nip up " and cause 

 to fall off from the branches the delicate blossoms of fruit 



(/) " Oysters and the Oyster Question." 



