LECTURE XII. 
213 
whicli require a calm sea, and thus another food 
from the animal kingdom is presented to strangers. 
The shallows also afford a quiet and desirable situ- 
ation to Mollusca, and shell-fish of all kinds, and 
^contribute greatly towards supplying the inhabit- 
ants of the islands with a variety of food. Thus 
we perceive that the Coral tribe, however insigni- 
ficant it may at first appear, is one of those power- 
ful engines in the hand of the Author of nature 
which can produce the most stupendous effects from 
the most seemingly weak and unpromising agents. 
After this general survey of the Zoophyte tribes 
I shall beg leave to direct your attention to a Class 
of Animals which, till the latter part of the seven- 
teenth century, had escaped all human attention and 
investigation, and constituted a kind of invisible 
world : a series of beings, the structure, powers, 
and properties of which, are perhaps more aston- 
ishing than those of most other animals : yet of 
such minuteness as, in general, to elude the sharp- 
est sight, unless assisted by glasses. The ancients 
therefore were totally unacquainted with this class 
of beings. To them the Mite was made the m 
plus ultra, or utmost bound of animal minuteness 5 
.but the moderns, assisted by the invention of the 
