4o8 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 

 pHcata), 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 trfivellcd so methodically along 



