4942 THE ZooLoGist—JUNE, 1876. 
25,000 eggs, and the entire spawn one anda half million. No male 
oyster has ever been seen to have any intercourse with an oyster in 
this condition. In the course of forty-eight hours the colour of 
“white sick” will have slightly altered, and assumed a grayish 
tinge. Ifexamined by the microscope, it will be found that this is 
due to the early formation of the oyster-shell. I believe that these 
shells are formed by the union of two eggs, thus, 00, and then the 
a ~_ ‘ ) 
addition of two more, giving the following appearance, 09, and that 
these eggs form the future shell and oyster. I do not state this 
positively, but rather as a guide to future observers. The same 
rule has been said to obtain in Buccinum. Of this, however, I am 
quite sure, that the continued change of colour in the eggs, from 
the pale tinge to their gray and sometimes almost black condition, 
is due to the gradual growth of the gray shell. 
The eggs are now what is termed “black sick,” and in this 
condition are believed by the unscientific to be the male, while the 
white spawn is said to be the female oyster! No statement can 
be more unfounded or more absolutely untrue than this. The 
eggs in their creamy condition give origin to the shells of the 
oysters, which grow larger and deeper in colour according to 
their age. 
Just before their emission from the shell, the young oyster itself 
may be observed working about a cluster of cilia—hair-like ap- 
pendages—which afterwards are withdrawn within the shell, and 
constitute the “beard.” The young oysters are now emitted into 
the water, and commence the business of life. Swimming about 
by means of their cilia, they seek out and at last find a resting-place, 
known by the name of “cultch.” To this “cultch” they attach ~ 
themselves, close to the hinge on the apex of the round shell, with 
the flat shell upwards. ‘The round or lower shell, which is, in fact, 
the habitat of the oyster, is immovable. The upper flat shell only 
has the power of motion, and is opened, and that by a specially 
adapted apparatus, for the rest of the oyster’s life. It follows, if 
you place an oyster at any period of its existence on the flat shell, 
it can only open as far as a yielding surface below will permit it. 
If the surface is sufficiently hard, the oyster cannot open, and must 
die. It must be remembered that the natural position of the oyster 
is a fixed one, the flat shell opening only at the will of the creature. 
As to annelids and other shelled things forming upon the round 
