TONGATABtt. 291 



of the more recent clearings is marked in the distance by the 

 projection from the main mass of dark foliage of the dead 

 branches of trees that have had their bark ringed. These, with 

 a species of Acacia (?), which at the time of our visit in winter 

 had a yellow tint upon its foliage, formed a marked feature in a 

 general view of the vegetation from a distance. 



There are naturally no indigenous mammals in Tonga except 

 bats. A large Fruit-bat, probably Pteropus keraudrenii which 

 occurs in Fiji and Samoa and also in the Caroline Islands,* is 

 very abundant. These Fruit-bats appear on the wing in the 

 early afternoon in full sun-light, and at the time of our visit 

 were feeding on the bright red flowers of one of the indigenous 

 trees. Flowers form an important proportion of the food of 

 Fruit-bats. In New South Wales, at Botany Bay in May, 

 numbers of Fruit-bats were to be seen feeding on the flowers of 

 the gum trees. The bats must probably often act as fertilizers, 

 by carrying pollen from tree to tree, adherent to their fur. 



As dusk comes on, the Fruit-bats on the wing become more 

 and more plentiful. It is probably only those specially driven 

 by hunger that come out before dusk. Besides these large bats, 

 there are small Insectivorous bats in Tonga, which dart about 

 amongst the cocoanut trees, but we obtained no specimens. 

 The heavy flap flap of the Pteropus is as strongly contrasted 

 with the rapid motion of the true bats, as is the flight of a goose 

 with that of a swallow. There are plenty of horses and cattle 

 in Tonga, and the high ground of Eua is occupied as a sheep 

 run. 



A small Heron (Demicgretta sacra) wades about on the coral 

 reefs at Tonga, and catches small fish, and is also to be seen fre- 

 quently inland all over the island. This bird changes its plumage 

 from pure white to uniform grey, and all stages of parti-coloured 

 plumage were to be seen during our visit. Contrary to the 

 usual rule, the bird is white when young, and dark in the mature 

 state. Hence the ancestors must have been white, and the race 

 is assuming a darker plumage for protection. 



In the groves, the most abundant bird is one about the size of 



* "Journal des Museum Godeffroy, Heft II. 1873." "Die Carolinen 

 Insel Yap oder Guap." 



D 2 



