334 MR. BOURNE ON THE FAUNA OF DIEGO GARCIA. [JuUC 29, 



Birgus latro, is also found and attains to a great size. I was never 

 able to watch a Birgus opening a cocoa-nut, though I several times 

 shut one up in a tub with a cocoa-nut for the purpose, but they 

 will not feed in captivity. Being nocturnal in their habits, these 

 animals are difficult to observe ; the account of them given by the 

 negroes agrees in all respects with that of Forbes in the work above 

 quoted. Many people have doubted that these "crabs" are able 

 to climb palm-trees ; but I have seen them do so myself, and I have 

 also seen one moiuat the slender stem of a " Bois de feu " till it 

 arrived at a projecting branch, along which it then proceeded to 

 climb, clinging underneath it like a sloth. Birgus, however, does 

 not mount the palms in order to rob them of the cocoa-nuts, but to 

 obtain shelter among the thick tuft of leaves at the summit. 



The large lagoon of Diego Garcia affords an excellent harbour, in 

 spite of the coral patches which rise to the surface in many places, 

 the courses for ships having been carefully buoyed out. The lagoon 

 abounds with fish, which are all eaten ; the most common sorts 

 caught by hook and line are the well-known Surgeon Fishes, 

 "Vielles" {Novacula), and some species of Percoids. Large Hammer- 

 headed Sharks {Zygcena malleus) are found in some parts of the 

 harbour, and specimens of the common Blue Shark {Oarcharias 

 glaucus) are very common. On one occasion we captured twenty- 

 three young specimens of this species in a single haul of the net. 



The climate is very damp and oppressive ; the thermometer 

 rarely exceeds 86° F. by day, or falls below 78° F. at night ; but 

 although the heat is not excessive, the heavy moisture-laden atmo- 

 sphere is very trying to European constitutions. 



An incredible amount of rain fell during my four months' stay on 

 the island ; it was only during the last three weeks of my visit that 

 we had anything like fine brilliant weather. On such days the 

 bright green foliage illuminated by the tropical sun, the dazzling 

 white sand bordering the lagoon, and the clear blue or, in the shal- 

 lower parts, green waters of the lagoon afford a striking picture of 

 peculiar beauty which is well worth seeing. 



I have to express my thanks to the authorities of the Orient 

 Steam Navigation Company, who faciliated my voyage in every way, 

 and kindly permitted me to reside at their coaling-station during a 

 large part of my visit ; and to M. Jules Leconte, the kind and hos- 

 pitable manager of the oil-stations on the main island, whose guest I 

 was for a long time, and who spared no trouble in assisting me in 

 jny researches. 



