408 
GALAPAGOS ARCHIPELAGO 
CHAP. 
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 transported 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 numbers which have been caught in a 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 likewise 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, 
and wallowing in the mud. The larger islands alone possess 
springs, and these are always situated towards the central parts, 
and at a considerable height. The tortoises, therefore, which 
frequent the lower districts, when thirsty, are obliged to travel 
from a long distance. Hence broad and well-beaten paths 
branch off in every direction from the wells down to the sea- 
coast ; and the Spaniards, by following them up, first discovered 
the watering-places. When I landed at Chatham Island, I 
could not imagine what animal travelled so methodically along 
