Fortunate Islands 
tissue, the result of a water life, has been utilised and 
developed to serve a totally different purpose, that of 
floating and so voyaging to distant islands. 
There are two groups of these navigators. One set 
consists of the mangroves and their attendant satellites. 
These are specially adapted to colonise muddy estuaries 
(see p.325). The rest are the ordinarycoral strand plants. 
Dr. Guppy found by actual experiments that the 
seeds of 95 per cent. of the eighty navigators were able 
to float ; 75 per cent. of them were kept in the water for 
two months, and showed no sign of losing buoyancy. 
For comparison he collected a hundred seeds of inland 
plants in one of these South Sea islands and found that 
75 per cent. of them sank immediately. 
The history of the colonisation of the Pacific Islands 
is still obscure, but the general course of it has been 
traced from Indo-Malaya to the eastward. As one 
proceeds east, the number of these navigator plants 
becomes gradually less. Tahiti, for instance, only pos- 
sesses fifty-five out of the eighty species recognised as 
characteristic, and it is only cosmopolitan species that 
have managed to reach the American coast-line. 
But the unfortunate point is that the ocean currents 
in the Pacific do not flow from west to east ; indeed, 
the north and south equatorial currents are exactly’ 
opposite to the apparent direction in which these plants 
have travelled. 
There are currents by which the navigators could travel 
without difficulty from the Malay peninsula as far as 
the Philippine Islands and even to New Caledonia, but 
from this point to Tahiti they have managed to travel 
against the regular drift, which is from east to west.* 
* Dr, Guppy suggests that during the north-west monsoon, that is, from 
January to March, some might have reached the Solomon Islands and others 
by the Caroline, Marshall, and Ellice groups. There is also the counter 
current (west to east), which might have been utilised by some of them. 
280 
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