45 
common oyster, and the large fresh-water muscle. 
turning round as it were upon a centre. This motion had 
been taken notice of by Lewenhoek, who thought it so ex¬ 
traordinary that he did not wish the fact to rest upon his own 
evidence, and called his wife and daughter, that they might 
bear testimony of its having taken place. When Mr. Bauer 
first met with it, the same notion occurred to him, of wishing 
to have other witnesses than his own eyes. He called in a 
young female servant, and having directed her eye upon the 
object, he asked what she saw ?—a little white thing turning 
round and round. 
This revolving motion of the embryo very naturally 
attracted my particular consideration; and having seen the 
porcelain manufactory at Worcester, it bore so close a resem¬ 
blance to the circular motion given to the pieces of clay out of 
which plates and saucers are formed, that for some time I was 
completely deceived ; but Mr. Bauer's close and persevering 
examination very soon detected the true cause of this strange 
phenomenon, which was produced by a small worm that had 
got into the vesicle, and while feeding on the embryo, per¬ 
formed these revolutions, carrying the young muscle round 
along with it, although itself concealed from the eye of the 
observer. 
The young remain in the oviduct, the interior of which has 
a greater resemblance to the honey comb in which the young 
bees are deposited, than any thing else I am acquainted with, 
till they arrive at the size fitting them to provide for them¬ 
selves ; they leave the oviduct in October and November. 
When the young are ready to leave their cellular prison, 
a canal is formed through which they pass out; and as the 
