The varieties of this family are not many; they are grouped in three
cases (24-26). Here are the terrible common crocodiles which have long
been the terror of the people whose native land they inhabit; the
alligators, which patronise America exclusively; and the gavials of
India. They are said to act as orderlies, in the rivers they frequent,
devouring all the putrid matter that would else infect the atmosphere.
Here too are those curious snakes which are equally thick at either
end--a peculiarity which has earned for them the appellation of
double-headed, and the supposed power of walking indifferently
forwards or backwards. The visitor now approaches the