RENNELL - AN OUT OF THE WAY CORAL ISLAND 213 



The coral limestone walls, partly covered with forest growth, rise sheer from the sea. 



pression. x'\lthough in course of time the water has become nearly fresh, 

 it is still brackish enough to be almost undrinkable. 



Rennell is quite a sizeable island, being about 75 kilometres long and 

 10 — 15 kilometres across. It lies WNW-ESE, more or less in line with the 

 prevailing trade winds, and is surrounded on all sides by ocean depths of 

 between 2,000 and 4,000 metres. 



In trying to form as correct a picture as possible of the fauna of so 

 restricted an area it is necessary to choose a characterictic small section 

 of each biotope — that is to say, of each locality (forest, shore, cultivated 

 land, etc.) — and then study it in full, collecting animals living on vege- 

 tation, on the ground, and under the ground. We divided the island into 

 five main biotopes: forest, cultivated land, lake and surroundings, shore, 

 and coral reef. 



The greater part of the area was covered by forest, and so we made a 

 thorough study both of a forest biotope near the coast and of another in 

 the middle of the island. The vegetation consisted of a comparatively 

 dense and not very tall tropical rain forest, with a few giant trees pro- 

 jecting here and there. 



The forest floor was astonishing. A thin layer of soil had formed here 

 and there, but in the great majority of places the ground consisted of the 



