APPENDIX 
OUTLINE CLASSIFICATION OF ANIMALS 
READERS who are not well acquainted with modern zoology 
may find the following outline classification useful for refer- 
ence. Fuller details will be found in any of the zoological 
text-books, e.g. Thomson’s Outlines of Zoology (Edinburgh), 
or the more systematic Natural Histories, e.g. The Royal 
Natural History (London). 
Of the terms used in modern classification, the word phylum 
is important. A phylum includes a group of animals 
whose members are characterized by a common ground-plan 
of structure, and are believed to have been descended from 
a common ancestor. Thus we distinguish the members of the 
phylum of vertebrates from all the varied phyla of inverte- 
brates by the fact that all have at some period of life a dorsal 
supporting rod called the notochord, possess a tubular nervous 
system, and have their respiratory organs, whether lungs or 
gills, originating from the anterior end of the food-canal. 
This phylum is divided into a number of smaller units or 
classes as follows : 
PHYLUM VERTEBRATA. 
Crass Mammattia, including warm-blooded hairy animals 
whose young are nourished by milk after birth, with three 
sub-classes : 
Sub-class I, Eutheria or Placentalia, the highest and most 
intelligent mammals, whose young are nourished before birth 
by an organ called the allantoic placenta, and are therefore 
born with the form of the adult; including nine orders. 
1. Primates, including monkeys, apes and man, as well as 
