THE VOYAGE OF THE BEAGLE 



413 



eggs, which they lay in their burrows: the inhabitants seek 

 them for food. 



These two species of Amblyrhynchus agree, as I have 

 already stated, in their general structure, and in many of 

 their habits. Neither have that rapid movement, so charac- 

 teristic of the genera Lacerta and Iguana. They are both 

 herbivorous, although the kind of vegetation on which they 

 feed is so very different. Mr. Bell has given the name to the 

 genus from the shortness of the snout: indeed, the form of 

 the mouth may almost be compared to that of the tortoise: 

 one is led to suppose that this is an adaptation to their 

 herbivorous appetites. It is very interesting thus to find a 

 well-characterized genus, having its marine and terrestrial 

 species, belonging to so confined a portion of the world. The 

 aquatic species is by far the most remarkable, because it is 

 the only existing lizard which lives on marine vegetable pro- 

 ductions. As I at first observed, these islands are not so 

 remarkable for the number of the species of reptiles, as for 

 that of the individuals; when we remember the well-beaten 

 paths made by the thousands of huge tortoises — the many 

 turtles — the great warrens of the terrestrial Amblyrhynchus 

 ■ — and the groups of the marine species basking on the coast- 

 rocks of every island — we must admit that there is no other 

 quarter of the world where this Order replaces the herbivo- 

 rous mammalia in so extraordinary a manner. The geologist 

 on hearing this will probably refer back in his mind to the 

 Secondary epochs, when lizards, some herbivorous, some 

 carnivorous, and of dimensions comparable only with our 

 existing whales, swarmed on the land and in the sea. It is, 

 therefore, worthy of his observation, that this archipelago, ' 

 instead of possessing a humid climate and rank vegetation, 

 cannot be considered otherwise than extremely arid, and, for 

 an equatorial region, remarkably temperate. 



To finish with the zoology: the fifteen kinds of sea-fish 

 which I procured here are all new species; they belong to 

 twelve genera, all widely distributed, with the exception of 

 Prionotus, of which the four previously known species live 

 on the eastern side of America. Of land-shells I collected 

 sixteen kinds (and two marked varieties), of which, with the 

 exception of one Helix found at Tahiti, all are peculiar to 



