886 GALAPAGOS ARCHIPELAGO. [ CHAP. XVII. 
large one weighed twenty pounds: on the island of Albemarle 
they seem to grow to a greater size than elsewhere. Their tails 
are flattened sideways, and all four feet partially webbed. They 
are occasionally seen some hundred yards from the shore, swim- 
ming about; and Captain Collnett, in his Voyage, says, “* They 
go to sea in herds a-fishing, and sun themselves on the rocks; and 
may be called alligators in miniature.” It must not, however, 
be supposed that they live on fish. When in the water this 
lizard swims with perfect ease and quickness, by a serpentine 
movement of its body and flattened tail—the legs being motion- 
less and closely collapsed on its sides. A seaman on board 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, it 
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 oftentimes 
be seen on the black rocks, a few feet above the surf, basking 
in the sun with outstretched legs. 
I opened the stomachs of several, and found them largely dis- 
tended with minced sea-weed (Ulve), which grows in thin 
foliaceous expansions of a bright green or a dull red colour. I 
do not recollect having observed this sea-weed in any quantity 
on the tidal rocks; and I have reason to believe it grows at 
the bottom of the sea, at some little distance from the coast. If 
such be the case, the object of these animals occasionally going 
out to seais explained. ‘The stomach contained nothing but the 
sea-weed. Mr. Bynoe, however, found a piece of a crab in one; 
but this might have got in accidentally, in the same manner as 
I have seen a caterpillar, in the midst of some lichen, in the 
paunch of a tortoise. The intestines were large, as in other 
herbivorous animals. The nature of this lizard’s food, as well 
as the structure of its tail and feet, and the fact of its having 
been seen voluntarily swimming out at sea, absolutely prove its 
aquatic habits ; yet there is in this respect one strange anomaly, 
namely, that when frightened it will not enter the water. Hence 
it is easy to drive these lizards down to any little point over- 
hanging the sea, where they will sooner allow a person to catch 
hold of their tails than jump into the water. They do not seem 
