28 THE MEANING OF EVOLUTION 
plant life in the tropics, and, like all naturalists, he 
was very enthusiastic over it. Among the animals 
that particularly attracted his attention was the sloth, 
a peculiar creature climbing slowly about the trees, 
small of size and sluggish of habit. Another animal 
that interested him greatly was the little armadillo 
with its interesting habit of curling up in its plated 
skin. 
Captain Fitzroy soon finished what work he was 
required to do in this neighborhood, and Darwin was 
called back to the Beagle to continue his voyage. 
When they arrived at the mouth of La Plata their 
most serious work began. Here there was much 
tedious charting for Fitzroy, and Darwin could now 
leave the vessel for a lengthy trip on shore. This 
was doubly welcome. Seasickness was nearly constant 
with Darwin while on this entire voyage and every 
opportunity to work on land was eagerly seized. This 
region, too, was rich in objects of interest and in 
strange people. While exploring the pampas, beyond 
Buenos Ayres, Darwin came across the skeletons of 
the great mammals some of which Cuvier had pre- 
viously described. He studied these bones with much 
care, and recognized at once in the megatherium a 
great similarity in structure to the sloth he had seen 
in Brazil. The enormous skeletons of the glyptodons 
struck him also as strangely similar to that of the ar- 
