300 A NATURALIST IN BORNEO 



increased in size as the associated animal has grown in 

 girth. If a crab be deprived of its burden, it manifests 

 every sign of disturbance, and hunts about the vessel in 

 which it is confined until it finds the object of its 

 search, which is then hoisted up in the two hinder 

 legs into the old position, the crab then backing down 

 into the mud until almost concealed from view. It is 

 \ difficult to imagine how the association of the two 

 creatures commences ; how does the newly formed crab 

 succeed in getting hold of a young unattached Sea- 

 Anemone ? That is a very pretty problem for some 

 one to settle. 



Opposite to Santubong the character of the sea-bottom 

 was different. Here no large river poured out its load 

 of mud, but instead were several smaller streams drain- 

 ing through mangrove swamps and carrying with 

 them waterlogged leaves and sticks. The sea-bottom 

 was of a harder sand, and here lived another Dorippe, 

 D. astuta, which did not bury itself in the sand, but 

 moved about freely. It was protected from observation 

 by a large leaf, which it invariably bore aloft in the 

 two hinder pair of legs, and with which it covered the 

 body completely. So close was the resemblance be- 

 tween one of these leaf-covered crabs and a waterlogged 

 leaf washing to and fro in the gentle bottom-currents, 

 that the closest scrutiny was needed to detect the 

 presence of the crab. I think no more remarkable 

 instance can be found of a wide difference in the 

 habits of two closely allied species differences evolved 

 in response to differences of environment. 



Lying some distance out at sea, off Santubong, are 

 three coral islets, the only examples of coral formation 

 within easy reach. The reefs were fringing reefs, but 



