606 
Badiata. 
unite and form one animal, though each section should 
belong to a different species. The head of one species 
may be engrafted on the body of another. When one 
Polyp is introduced by the tail into another's body, the 
two heads unite and form one individual. Pursuing 
these strange operations, M. Trembley gave scope to his 
fancy by repeatedly splitting the head and part of the 
body ; he thus formed hydras more complicated than ever 
struck the imagination of the most romantic fabulist. 
Though so difficult, to destroy by division, all the 
Polyps, even those which form the corals, may be easily 
killed by depriving them of moisture, when they soon 
shrivel up, and the tissue of their skins is completely 
destroyed. 
Of these Fresh-water Polypi, only a few kinds are 
known, but the sea nourishes a multitude of species 
which closely resemble the Hydras in their structure, 
from hence called Hydroid Polyps by Cuvier and many 
other naturalists. Most of these are compound creatures, 
of the kind shown in the above engraving, of which 
many species may be found on all our shores. A horny 
tube runs branching over the surface of a seaweed, or 
