416 
GALAPAGOS ARCHIPELAGO 
CHAP. 
having its marine and terrestrial species, belonging to so con¬ 
fined 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 productions. 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 herbivorous 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 this archipelago: 
a single fresh-water shell (Paludina) is common to Tahiti and 
Van Diemen’s Land. Mr. Cuming, before our voyage, procured 
here ninety species of sea-shells, and this does not include 
several species not yet specifically examined, of Trochus, Turbo, 
Monodonta, and Nassa. He has been kind enough to give me 
the following interesting results : of the ninety shells, no less 
than forty-seven are unknown elsewhere—a wonderful fact, 
considering how widely distributed sea-shells generally are. Of 
the forty-three shells found in other parts of the world, twenty- 
five inhabit the western coast of America, and of these eight 
are distinguishable as varieties ; the remaining eighteen (including 
one variety) were found by Mr. Cuming in the Low Archipelago, 
and some of them also at the Philippines. This fact of shells 
