416 PERCY SLA DEN TRUST EXPEDITION 



It covers the greater part of Aldabra, and in conjunction with the " champignon " 

 rock forms the great obstacle to exploration. It is quite useless, for the timber is too 

 small, and the bark, though reputed rich in tannin, would not pay removing. 



3. Open bush is found in the neighbourhood of Takamaka and extends round the 

 atoll eastward as far as a line drawn from Michel Island to Hodoul point ; to the west- 

 ward it extends nearly to Dunes Jean Louis, but in this direction is much reduced in size 

 by the shore-zone passing far inland. Plain Cabris on Picard Island also supports the 

 same type of vegetation. It is always coincident with "platin" rock which is such that 

 a little soil (largely formed of guano) can collect on its surface. The vegetation is mostly 

 formed by low trees and bushes. Hei'baceous plants are scarce and are only found in the 

 wet season, when a few sedges and grasses occur in places. The bushes and trees are 

 usually leafless, or partially so, in the dry season and flower at the commencement of the 

 rains, often before the leaves appear. 



Almost all the Aldabra plants are to be found in this type of country. A few that are 

 easily recognised are Euphorbia Abbotti, various species of Ficus, two species of Grewia, 

 several papilionaceous plants {Mimosa ?, CcBsalpinia, Cassia). A thorny (rosaceous ?) 

 bush is not uncommon, and large clumps of Pandanus Vandermeeschii are very frequent. 

 The majority of the plants in this country, however, were not identified in the field. 



4. The shore-zone extends all round the atoll varying much in size. It owes its 

 existence to a little soil formed of sand blown up from the reef and is naturally therefore 

 widest on the south-east coast. Characteristic plants are Sccevola Koenigii, Tournefortia 

 argentea, and in places Cordia subcordata. At intervals large clumps of Pandanus exist, 

 and very stunted bushes of Pemphis acidula are found on the south coast. 



A few exceptional patches of vegetation, almost jungle, occur, the chief being on 

 Esprit Island, which contains several plants scarce elsewhere. Picard Island has a peculiar 

 bush, which, though very dense, is formed of the same plants as ordinarily form the " open 

 country." Couroupa, which has a deep sandy soil, supports a mixed vegetation, partly of 

 " open country " plants but mainly of " shore-zone " forms. 



Casuarina* has established itself at Picard and Michel Islands, and on each side 

 of Grande Passe and Passe Houareau ; other introduced plants are found to some extent 

 on Picard but the conditions are such that few fresh plants can obtain a foothold. 



Fauna. (a) Mammalia. The only indigenous mammals belong to the order 

 Chiroptera ; the most interesting being a peculiar species of Fruit-eating Bat {Pteropus 

 aldabrensis, True f). It is a rather small species and is peculiar in having the bony 

 orbit complete, a feature which it shares with Pteropus nicobaricus. Its food consists 

 of the fruit of the banyan (Ficus sp."?) and when obtainable of the "takamaka" 

 {Calophyllv/m inophyllum), while coconut flowers are also much sought after. The species 

 is often observed flying by day as well as night, though it was most active in the bright 

 moonlight. It never forms large gatherings on a tree during the daytime, as is the case 

 with the Seychelles flying fox (Pterop>us edwardsii). 



* Casuarina equisetifolia. [Of course introduced.] 

 t Proc. U.S.A. Mus. 1893, Vol. 1G, p. 533. 



