382 GALAPAGOS ARCHIPELAGO. [CHAP. XVIT. 
any of the volcanic islands in the great oceans. As far as I can as- 
certain from various works, this seems to hold good throughout the 
Pacific, and even in the large islands of the Sandwich archipelago. 
Mauritius offers an apparent exception, where I saw the Rana 
Mascariensis in abundance: this frog is said now to inhabit the 
Seychelles, Madagascar, and Bourbon; but on the other hand, 
Du Bois, in his voyage in 1669, states that there were no reptiles 
in Bourbon except tortoises ; and the Officier du Roi asserts that 
before 1768 it had been attempted, without success, to introduce 
frogs into Mauritius—I presume, for the purpose of eating: 
hence it may be well doubted whether this frog is an aboriginal 
of these islands. The absence of the frog family in the oceanic 
islands is the more remarkable, when contrasted with the case of 
lizards, which swarm on most of the smallest islands. May this 
difference not be caused, by the greater facility with which the 
eggs of lizards, protected by calcareous shells, might be trans- 
ported through salt-water, than could the slimy spawn of frogs? 
I will first describe the habits of the tortoise (Testudo nigra, 
formerly called Indica), which has been so frequently alluded 
to. These animals are found, I believe, on all the islands of the 
Archipelago; certainly on the greater number. They frequent 
in preference the high damp parts, but they likewise live in the 
lower and arid districts. I have already shown, from the num- 
bers which have been caught ina single day, how very numerous 
they must be. Some grow to an immense size: Mr. Lawson, an 
Englishman, and vice-governor of the colony, told us that he 
had seen several so large, that it required six or eight men to lift 
them from the ground; and that some had afforded as much as 
two hundred pounds of meat. The old males are the largest, 
the females rarely growing to so great a size: the male can 
readily be distinguished from the female by the greater length 
of its tail. The tortoises which live on those islands where 
there is no water, or in the lower and arid parts of the others, 
feed chiefly on the succulent cactus. Those which frequent the 
higher and damp regions, eat the leaves of various trees, a kind 
of berry (called guayavita) which is acid and austere, and like- 
wise a pale green filamentous lichen (Usnera plicata), that hangs 
in tresses from the boughs of the-trees. 
The tortoise is very fond of water, drinking large quantities, 
