THE LIVING WORLD. 
work on the subject treated by The Living World will be found more 
complete or more satisfactory for any one desiring the real knowledge 
which persons at large wish in regard to subjects which do not directly form 
a part of their daily life. No one more than myself can appreciate so 
fully the distance between desire and achievement; but many may justify my 
belief that there is need for information which a person in active life 
has not time to ex¬ 
tract from mere data,, 
especially when these 
are obscured by 
technical terms. The 
changes of animals 
when domesticated 
have been sufficiently 
used in illustration 
of the fact that it lies 
within the opportuni¬ 
ties of any one to 
watch the method 
which the Creator has 
prescribed as the law of 
animal life, and which will be further exhibited in the descriptions which follow. 
the urchin ( Echidna hystrix ) and duck mole swimming. 
MONOTREMES. 
The Duck-billed Platypus (Ornithorhyncus anatinus) is aquatic, and 
may well serve as a link between birds and mammals. It is about a foot and 
three-quarters in length, and its 
long, flat, otter-like body is clad 
in soft, thick fur, brown above 
and whitish beneath. Its toes 
are united by a membrane, its 
tail is flat and obtuse, and its 
broad, elongated muzzle looks 
as if it had been borrowed from 
the duck. It burrows in the 
banks of streams, and is there¬ 
fore called river mole or mul- 
ligong. The animal is, as has 
been said, properly aquatic, but 
it can move about on land, and 
even climb, though in the latter 
exercise it braces its body 
against two opposite walls and 
wriggles itself up in a way 
quite well known to the fertile- porcupine echidna. 
minded “ small boy.” It is 
Australian in its habitat, and may well serve the purpose of marking the 
transition from the highest types of birds to the lowest forms of the mammals. 
The Echidna, or Porcupine Ant-eater (.Echidna hystrix , or aculeata . or 
