58 ANIMAL COLORATION. 



length of a full-grown one is about a yard, but there are some 

 even four feet long. I have seen a large one which weighed 

 twenty pounds. These lizards are occasionally seen some 

 hundred yards from the shore, swimming about; and Captain 

 Collnett, in his "Voyage," says that they go out to sea in shoals 

 to catch fish. With respect to the object, I believe he is 

 mistaken, but the facts stated on such good authority cannot 

 be doubted. When in the water the animal swims with 

 perfect ease and quickness, by a serpentine movement of its 

 body and flattened tail, the legs during this time being per- 

 fectly motionless and collapsed on its sides. A seaman aboard 

 sank one with a heavy weight attached to it, thinking thus to 

 kill it directly; but when, an hour afterwards, he drew up the 

 line, the lizard was quite active. Their limbs and strong claws 

 are admirably adapted for crawling over the rugged and fissured 

 masses of lava which everywhere form the coast. In such 

 situations, a group of six or seven of these hideous reptiles may 

 often be seen on the black rocks, a few feet above the surf, 

 basking in the sun with outstretched legs." These powerful 

 beasts would hardly need protection: and as they feed upon 

 vegetable substances, they do not need to resemble their 

 surroundings for aggressive purposes. 



There are other examples among the inhabitants of the 

 Galapagos archipelago of a darker coloration than that of 

 their allies upon the neighbouring mainland. 



Mr. Salvin, in his exhaustive account of the avifauna of this 

 group of islands,* mentions several instances of birds which are 

 hardly to be distinguished as peculiar in the species except by 

 their darker coloration. An owl (Asio yalapayoensis) closely 

 resembles the world-wide Short-eared owl (Asio bracliyotus}, and 

 is only to be distinguished by its darker hues. Similarly a 

 * Trans. ZooL .SV*c., vol. ix., 1876. 



