10 ST. PAUL’S ROCKS. [cuap. 1, 
shells, of all living animals, it is an interesting physiological 
fact * to find substances harder than the enamel of teeth, and 
coloured surfaces as well polished as those of a fresh shell, re- 
formed through inorganic means from dead organic matter— 
mocking, also, in shape some of the lower vegetable productions. 
We found on St. Paul’s only two kinds of birds—the booby 
and the noddy. The former is a species of gannet, and the 
latter a tern. ‘Both are of a tame and stupid disposition, and 
are so unaccustomed to visitors, that I could have killed any 
number of them with my geological hammer. The booby lays 
her eggs on the bare rock; but the tern makes a very simple 
nest with seaweed. By the side of many of these nests a small 
flying-fish was placed; which, I suppose, had been brought by 
the male bird for its partner. It was amusing to watch how 
quickly a large and active crab (Graspus), which inhabits the 
crevices of the rock, stole the fish from the side of the nest, as 
soon as we had disturbed the parent birds. Sir W. Symonds, 
one of the few persons who have landed here, informs me that 
he saw the crabs dragging even the young birds out of their 
nests, and devouring them. Not a single plant, not even a 
lichen, grows on this islet; yet it is inhabited by several insects 
and spiders. The following list completes, I believe, the ter- 
restrial fauna: a fly (Oltersia) living on the booby, and a tick 
which must, have come here as a parasite on the birds; a small 
brown moth, belonging to a genus that fecds on feathers; a 
beetle (Quedius) and a woodlouse from beneath the dung; and 
lastly, numerous spiders, which I suppose prey on these small 
attendants and scavengers of the waterfowl. The often repeated 
description of the stately palm and other noble tropical plants, 
then birds, and lastly man, taking possession of the coral islets 
as soon as formed, in the Pacific, is probably not quite correct; 
I fear it destroys the poetry of this story, that feather and dirt- 
* Mr. Horner and Sir David Brewster have described (Philosophical 
Transactions, 1836, p. 65) a singular “ artificial substance resembling shell.” 
It is deposited in fine, transparent, highly polished, brown-coloured laminze 
possessing peculiar optical properties, on the inside of a vessel, in which 
cloth, first prepared with glue and then with lime, is made to revolve rapidly 
in water. It is much softer, more transparent, and contains more animal 
matter, than the natural incrustation at Ascension; but we here again see 
the strong tendency which carbonate of lime and animal matter -evine 
form a solid substance allicd to shell. ance to 
