EXPLANATION OF THE CHART OF THE ORDERS OF MAMMALS. 
To the beginner in Natural History studies, the Order is the master-key to classification. 
This Chart is based on the well-known fact that in the pursuit of a difficult study, any scheme 
which properly and truthfully appeals to the eye is an aid both to the understanding and the mem- 
ory. It shows the relative importance of the various Orders of Mammals, but not their relative 
sizes, based on the number of species in each, as has been done later on with the birds. If number 
of species were given precedence over economic importance, the Order Glires would dominate, and 
the Order Ungulata would appear small and insignificant. 
It is impossible to construct a diagram which will show correctly the relations which the various 
Orders bear toward each other, anatomically. This is because some Orders are characterized by 
their teeth, some by their feet, or hands; others by their wings, and two by their mode of producing 
their young. 
It will be noted that: 
The Primates, of the tree-tops, have the highest position. 
The Cete, which in some respects are the lowest of the Mammalia, occupy the lowest position. 
The Bats are shown in mid-air, and the Insectivores appear under ground, where they live out 
their lives. 
The Seals and Sea-Lions appear both on the shore and in the sea, and the Sirenians are located 
in an estuary. 
The Ferae, Glires and Ungulata spread throughout the whole visible earth, covering forest and 
plain, sea, pond and stream, from the sea to the most distant mountains. 
The Monotremates, or egg-laying mammals, are quite apart from all other land mammals, and 
appear low down, near the home of the ducks, as shown on the bird chart. The space allotted 
to this strange Order has been made egg-shaped, to suggest the leading characteristic of its 
members. 
