109 



twenty-two miles long by eight miles in its greatest breadth, 

 oblong-oval in outline, and with its longer axis lying east and 

 west. The land-rim is broken up into four islands of odd shapes, 

 very unequal in size, the main island surrounding at least two- 

 thirds of the lagoon. Within the lagoon there are several 

 islands of relatively large area and hundreds of small islet- 

 varying in size from a few acres to a few square yards. The 

 inner or lagoon shore of the land-rim is everywhere bounded 

 mangrove swamps, intersected by numerous channels. In 

 length the lagoon is about twenty miles with a width of six 

 miles, and it is connected with the open sea by four channels, 

 the largest of which is four hundred yards wide and eight iu 

 ten fathoms deep, and the only one deep enough to allow of the 

 passage of a large vessel. Mr. J. C. F. Fiver describes in some 



detail the topography, physical features, etc., of Aldabra, and 

 it will be sufficient for the purposes of this paper to give a 

 short extract from his work concerning the islands which he 

 designates the Aldabra series. " It contains the islands of 

 Aldabra, Assumption, Cosmoledo, Astove, Farquhar, Provi- 

 dence and St. Pierre. The whole series lies to the north of 

 Madagascar, between longitudes 45° E. and 52° E., and between 

 latitudes 9° S. and 10*5° S., the component islands being 

 separated from 20 miles — Aldabra and Assumption — to 180 miles 



•Astove and Farquhar." 



For purposes of comparison I have also summarised very 

 briefly what is known to me of the botany of Gloriosa, the 

 Amirantes group, Coetivy, Agalega, Cargados, the Laccadives, 

 Maldives, and the Chagos Archipelago. 



Climate. 



■ 



There are few statistics of the meteorology of Aldabra, but 

 there are sufficient data to establish the fact that its climate is 

 one of extremes of drought and rainfall. Writers differ widely 

 in their estimate of its qualities. Professor Stanley Gardiner, 

 writing of Mr. Fryer's stay in the island (September to the end 

 of January), says: " His work during this, the summer season 

 at Aldabra, must have been, as we know by our own experience 

 elsewhere, arduous in the extreme on an island of jagged coral, 

 covered with the hard-wooded Pemphu acidula, through which 

 all paths had to be cut, and having in the centre a stinking 

 mangrove swamp literally alive with mosquitoes. Even native 

 labour dislikes going to Aldabra, which has an evil reputation 



second to none in the world." 



Voeltzkow, as quoted by Schinz, says: "Aldabra lies within 

 the range of the trade winds and has an agreeable climate, as 

 the cool sea winds temper the great heat. The average tempera- 

 ture at mid-day, from the middle of April to the middle of May, 

 is 85° to 86° Fahr. with a nightly fall of about 10°. The rainy 

 season begins in December, but showers are frequent even in 

 May. The dry season begins towards the month of July." 



Mr. Dupont records a series of observations of temperature 

 and rainfall from October to January. He states that the 

 climate of Aldabra is much warmer than that of Mo he, and 



