294 A NATtfRALIST IN BORNEO 



interchange of species as are the seas which separate 

 islands. Most of the species common to both Matang 

 and Santubong were widely distributed lowland forms, 

 analogous with those widely distributed mainland forms 

 which spread on to adjacent islands. 



The sea that washes the Sarawak coast affords a 

 comparatively poor harvest to the naturalist, for it is 

 shallow and the bottom is of fine mud, discharged by 

 the great rivers, which, in a country where the annual 

 rainfall averages about 130 inches, are always swollen 

 and turbid. As I considered it of more importance to 

 collect land animals than marine, I never devoted a 

 great deal of attention to the latter. The marine fauna 

 of the tropics stands in no danger of decrease on 

 account of the depredations of man, whereas even in 

 Sarawak, that peaceful backwater of civilization, there 

 have been notable alterations in the land fauna in the 

 neighbourhood of towns and Government stations 

 within the last twenty-five years, whilst the natives 

 themselves, by their extravagant system of cultivation, 

 whereby tracts of jungle are annually destroyed, must 

 be responsible in the long run for the extermination 

 of many species. Still, it was not possible to live any 

 length of time at Santubong without taking at least 

 a passing interest in the animals which were to be 

 found on the river-banks and seashore. 



I had a great ambition at one time to investigate 

 thoroughly the fauna of the mangrove-swamps, and 

 determined to make a beginning by excavating the 

 burrows of that aberrant Crustacean, Thalassina anomala, 

 a sort of Crayfish. These creatures burrow deeply in 

 the mud, throwing up a large cone of the material 

 that they have excavated. One roasting hot morning 



