Chap. YI. 
AFFINITIES AND GENEALOGY. 
213 
carry us on to the amphibians. We have seen that 
birds and reptiles were once intimately connected 
together ; and the Monotremata now, in a slight degree, 
connect mammals with reptiles. But no one can at 
present say by what line of descent the three higher 
and related classes, namely, mammals, birds, and rep- 
tiles, were derived from either of the two lower verte- 
brate classes, namely amphibians and fishes. In the 
class of mammals the steps are not difficult to con- 
ceive which led from the ancient Monotremata to 
the ancient Marsupials; and from these to the early 
progenitors of the placental mammals. We may thus 
ascend to the Lemuridse ; and the interval is not wide 
from these to the Simiadae. The Simiadae then branched 
off into two great stems, the New World and Old World 
monkeys; and from the latter, at a remote period, Man, 
the wonder and glory of the Universe, proceeded. 
Thus we have given to man a pedigree of prodigious 
length, but not, it may be said, of noble quality. The 
world, it has often been remarked, appears as if it had 
long been preparing for the advent of man ; and this, in 
one sense is strictly true, for he owes his birth to a long- 
line of progenitors. If any single link in this chain 
had never existed, man would not have been exactly 
what he now is. Unless we wilfully close our eyes, we 
may, with our present knowledge, approximately re- 
cognise our parentage ; nor need we feel ashamed of it. 
The most humble organism is something much higher 
than the inorganic dust under our feet ; and no one 
with an unbiassed mind can study any living creature, 
however humble, without being struck with enthusiasm 
at its marvellous structure and properties. 
