490 GALAPAGOS ARCHIPELAGO. [cHap. xv1L 
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 characteristic of the genera 
Lacerta and Iguana. They are both herbivorous, although the 
kind or 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, be- 
cause it is the only existing lizard which lives on marine vege- 
table 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 extra- 
ordinary 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, in- 
stead of possessing a humid climate and rank vegetation, cannot 
be considered otherwise than extremely arid, and, foran equa- 
torial 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 ge- 
nera, all widely distributed, with the exception of Prionotus, of 
which the four previously known species live on the eastern side 
of America. Of Jand-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 Die- 
men’s Land. Mr. Cuming, before our voyage, procured here 
ninety species of sea-shells, and this does not include several 
