8 PERCY SLADEN TRUST EXPEDITION. 
Saya de Malha and the partially submerged Nazareth, Amirante, and Seychelles Banks. 
The presence of hills marked in the charts of many of the islands between the Seychelles 
and Madagascar pointed to the possibility of their being in an area of elevation. And, 
finally, we required more definite information as to the existence of raised coral- 
limestones in Mauritius and the Seychelles. The distribution of the fringing reefs 
in the latter locality, as marked on the charts, seemed unusual, while in Farquhar we 
hoped to find a new type of shallow-lagooned atoll which would throw some light 
on Aldabra—an island of great interest from the presence of gigantic land-tortoises 
( Testudo elephantina). 
Such were the chief motives which directed the course of the Expedition. How far 
they have been successful we must leave others to judge, when the reports are all 
published. In addition to these main objects much routine-work was involved, such as 
the taking of water-samples, temperature observations, plankton collections, and in 
noting meteorological phenomena. From the commencement of our work we recognised 
the necessity of restricting ourselves to limited areas, instead of spending time in 
making isolated observations during the long ocean-passages. Yet we now feel that our 
ground and work were several times too large for the time and facilities at our disposal. 
We cannot, we fear, do more than claim to have, in some degree, paved the way for 
another expedition over the same area, and by our failures and successes to have 
indicated problems to be solved and their most promising methods of attack. 
Il. History AND EQUIPMENT OF THE EXPEDITION. 
Undoubtedly the greatest biological expedition ever sent out by any country was 
that of H.M.S. ‘Challenger.’ It stands pre-eminent in originality and comprehensiveness 
of aim, in duration, and in results. It investigated every side of oceanography, lasted 
over four years, and extended round the whole world; in its publications, to which 
many of the most distinguished men in Europe contributed, it brought new facts to 
light bearing on every aspect of the ocean and on every group of animals and plants. 
‘True, it was only a pioneer expedition, but the far-sightedness of its director and of the 
editors of its reports made it a model which has rarely been equalled, never surpassed, 
by the few expeditions which have since left, European and American shores. 
Only one ocean was omitted in the scheme of the ‘Challenger’ Expedition, the 
Indian, which, it was confidently believed, would be subsequently examined by the 
enterprise of the Indian Government—an anticipation which thirty years afterwards 
still awaits any attempt at verification. Meantime this ocean has become much better 
known in its topographical and physical features by the exertions of H.M. Surveying 
Vessels belonging to the ome and Indian Governments, by the soundings of Telegraph 
Companies, and a special German scientific expedition, that of the ‘ Valdivia.” Except 
for the latter, and for such observations as the naturalists on the Indian Survey-Ship 
‘Investigator’ were permitted to undertake, its biology remained almost unknown, 
though the work of numerous naturalists on its continental coasts gave us a fair idea of 
their fauna and flora. ‘The ‘ Valdivia’ Expedition made a rapid traverse along a route 
