18 
THE RACES OF THE ALDABRA GROUP. 
All the living gigantic Tortoises which have been brought to Europe from the Indian 
Ocean within the last forty years are distinguished by the presence of a nuchal shield, 
convex cranium, and narrow obturatoric bridge. Whenever it has been possible to 
trace their origin this was found to be Aldabra, a group of small islands north-west of 
Madagascar, situated in lat. 9° 25' S., long. 46° 20' E. Although the majority of the 
specimens were shipped at Mauritius or the Seychelles, they had been brought there, 
in the first instance, from Aldabra, to be kept as curiosities or for the sake of their flesh 
or that of their progeny, which, in that suitable climate, they annually yielded to their 
owners with great regularity. 
It is not at all impossible, nay, probable, that some of the other insignificant islands 
which are scattered in the same part of the Indian Ocean likewise harboured this Chelo- 
nian type ; but of this I cannot find anywhere in the old records positive evidence. If it 
was so, the Tortoises were speedily exterminated, as the islands, from their small size, 
could not off"er to them any place of effectual concealment. These islands seem to have 
been formerly much more frequently visited by ships on their way to or from India 
than at present, when they are rather avoided. 
Among the specimens united by the common characters stated above, not unimpor- 
tant differences may be observed ; they are difficuit to reconcile with our ideas about 
the amount of variability within the limits of the same species or race ; but we can 
account for them by assuming that the animals came from diff"erent though neighbour- 
ing islands. More especially the islands of which the Aldabra group consists are 
separated by narrow deep channels of the sea, perfectly impassable to animals so help- 
less in the water as Land-Tortoises. In other respects the islands are described as 
covered with verdure, low tangled bushes interspersed with patches of white sand. Two 
of the islands are rather low, liummocky near the centre. The third island is the 
largest, extending about eighteen sea-miles in length and two or four miles in breadth ; 
it is much higher than the others, and partly covered with very high trees, that may be 
seen eight or nine leagues from the deck of a moderate-sized ship. Besides these three 
larger islands, there are several very small outlying islets. The first record of the 
existence of Land-Tortoises in Aldabra I find on a map of this group given by 
