6 THE VOYAGE OF H.M.S. CHALLENGER. 
observation and even experiment would be essential ; and this was naturally out of the 
question owing to the short period of time passed at each reef-station by the Challenger. 
In the compilation of the lists of the species which are known to occur at each of the 
Challenger reef-stations, published localities have been alone considered, and with this 
limitation it is believed that the lists are fairly complete as regards the more’ definitely 
marked reef-building forms. Considerable difficulty has been experienced, however, in 
deciding between various simple forms, which, although not among the usually recognised 
reef-builders, are yet either shallow-water forms or forms from the comparatively deeper 
waters of the reef-areas. 
In the case of many of the species described or recorded by the older authors, though 
it is certain that many of them must occur at one or more of the stations named, yet it 
was impossible to incorporate them owing to the want of a definite record of the locality ; 
while, on the other hand, in many eases it seems to me equally impossible to be certain, 
either from the figures or from the descriptions, what species were really intended. 
Though the lists may possibly be found incomplete, yet it must be pointed out, 
particularly to those who have not full opportunity for consulting the whole literature on 
the subject, that the simple record of a species is not always sufficient for its location, 
that often a knowledge of its history is required. Of this, a case in pot may be taken 
from the record given by Dana of the occurrence of Fungia echinata, Pallas, in the 
Fiji Islands. Specimens from the East Indies (Singapore) and from the Fiji Islands 
were referred to this species by Dana; but it has been shown by Milne-Edwards and 
Haime that the specimens were not referable to Fungia echinata, but to a new species 
Fungia danex, which they also record from Manilla as well as from the East Indies and 
the Fiji Islands. Following on this, however, it has been shown by Verrill that, while 
the original Singapore specimens of Dana are forms of Fungia danex, the Fiji specimens 
are distinct and belong to a new species, Fungia lacera; so that while lists from 
Dana or from Milne-Edwards and Haime would include Fungia echinata or Fungia 
dane from the Fiji Islands, the fact is that neither of these species is as yet recorded 
from that locality, but only the Fungia lacera. 
The detailed list of the species now known from each locality has been given, with 
the hope not only that it will prove of use to those who may be working at the Fauna 
of the island or groups of islands represented, but more especially that it may serve as 
a basis for, or as a first instalment to, a knowledge of the distribution of the Reef-Corals. 
Little or no attempt has been made to generalize from the facts at hand as to the 
relations of the Fauna of the various groups, since it was impossible not to recognise how 
incomplete was the knowledge of them that we at present possess. Nor does it seem 
possible that such generalizations can safely be made until at least such examinations of 
the Coral fauna of the chief groups of the Pacific and Indian Oceans have been made as 
have been accomplished in the case of the Corals of the Red Sea. 
