10 FARM ANIMALS 
of rivers in Australia and Tasmania. This mammal 
lays two eggs at a time. The eggs have a yolk. A kindred 
form, the spiny ant eater, hatches its eggs in a temporary 
pocket that disappears when 
the young grow big enough to 
care for themselves. The step 
from these to the Marsupiala, 
the characteristic mammals of 
southern Asia, the opossum of 
America, and the kangaroo of 
Australia, is not difficult to 
Duck MOLE . Bia a3 
These animals live on worms and COVEY. The most distinctive 
vegetable matter. a : 
eliory est character of mammals is their 
mode of development and of nourishment during the 
earliest period of life. They are all brought into the 
world alive. 
The lowest mammals are more closely related to reptiles than to 
birds. Reptiles are also egg layers. 
In the earlier ages man must have attempted to use 
many forms of animal life. The number of species that 
he has succeeded in domesticating either for food, cloth- 
ing or labor has, indeed, been small. Of the numerous 
types described in this lesson man depends almost exclu- 
sively upon animals with backbones and has domesti- 
cated in the true sense only birds and mammals. 
