ety 
veral of the helices are found to congregate in vast 
numbers. The ocean swarms with meduse. The 
congregation of coral insects forms islands in the 
Pacific ; yet the isis hippuris, or jointed coral, the 
antipathes, or black coral, and the gorgonia nobilis, 
or red coral, have great analogy with solitary plants. 
They are produced apparently from the beginning 
of time in the same, or nearly the same places, but 
they have no connection of common impulses. They 
are separately fixed, by apparent roots, to rocks: 
these, however, are not real roots, for they do not im- 
bibe nourishment. The animals exactly resemble 
plants covered with soft flesh, which exhibits nume- 
rous cells, or polypiformed mouths, which serve to 
imbibe nourishment, and to send forth spawn. A 
common impulse to hybernation compels garden 
snails to assemble toward the approach of winter, 
and to cluster together in some appropriately chosen 
cavity for shelter against frost, and other sources of 
injury. 
The arachnides are for the most part solitary, and 
ferocious in destroying intruders on their solitude, 
even those of their own species. 
The gossamer spiders appear, however, to be an 
exception. See Letter 65 of White’s Natural His- 
tory of Selborne, where he mentions a shower of 
gossamer extending about eight miles in every di- 
rection and many hundred feet in height, according 
to the notice of a person who rode up the side of a 
steep hill above 300 feet, and found the gossamer 
still far above him. The scorpion, scolopendra, and 
13 
