SCIENCE AND TRAVEL 209 



can carrion-hawk. There were three species of mock- 

 ing-thrush, two of them confined to one island each. 

 There were thirteen species of finches, all peculiar to 

 the archipelago. In the different species of geospiza 

 there is a perfect gradation in the size of the beaks, 

 only to be appreciated by seeing the specimens or 

 their illustrations. 



Few of the birds were of brilliant coloration. 

 The same was true of the plants and insects. Darwin 

 looked in vain for one brilliant flower. This was in 

 marked contrast to the fauna and flora of the South 

 American tropics. The coloration of the species sug- 

 gested comparison with that of the plants and animals 

 of Patagonia. Amid brilliant tropical plants brilliant 

 plumage may afford means of concealment, as well 

 as being a factor in the securing of mates. 



Darwin found the reptiles the most striking fea- 

 ture of the zoology of the islands. They seem to take 

 the place of the herbivorous mammalia. The huge 

 tortoise (Testudo nigra) native in the archipelago 

 is so heavy as to be lifted only by six or eight men. 

 (The young naturalist frequently got on the back of 

 a tortoise, but as it moved forward under his encour- 

 agement, he found it very difficult to keep his bal- 

 ance.) Different varieties, if not species, characterize 

 the different islands. Of the other reptilia should 

 be noted two species of lizard of a genus {Ambly- 

 rhynchus) confined to the Galapagos Islands. One, 

 aquatic, a yard long, fifteen pounds in weight, with 

 " limbs and strong claws admirably adapted for crawl- 

 ing over the rugged and fissured masses of lava," 

 feeds on seaweed. When frightened it instinctively 

 shuns the water, as though it feared especially its 



