2 ANIMAL COMMUNITIES 
in the same area the botanist would probably find only about 2,000 
conspicuous plant species. Representatives of all animal species must 
be submitted to specialists for identification, that is, the specialist 
gives the correct scientific name to the animal. Scientific names are 
definitely arranged as below, if man is taken as an example. 
Phylum - - - - Chordata or Vertebrata 
Class - - - - - - Mammalia 
Order - - - - - - Primates 
Family - - : - - - Hominidae 
Genus”) - - . - - - - Homo 
Species. - - - - - - - sapiens 
The young of many insects and of some other animals cannot be 
placed in the proper species because animal life histories are very imper- 
fectly known. Such animals are merely placed in the proper genus or 
family. The common names of animals rarely apply to single species 
but to whole genera, families, or even orders. “‘Caddis-worm”’ is a name 
applied to a whole order of insect larvae and as these are very imper- 
fectly known the term caddis-worm is applied to many species, and, 
applied in this way, appears in many places in the text. 
Because of the large number of animals and the difficulty in naming 
them, it is quite impossible to deal with the data in the specific way that 
might be possible with plants. Furthermore, while the data for plant 
distribution are not well known, those for animal distribution are much 
less well known. Therefore in most cases it is necessary to speak in 
general terms. It is impossible and undesirable to discuss each com- 
munity of animals in detail. The facts are not known, and even if they 
were known, their volume would be such as to exclude the great majority 
of them from the limits of this treatise. In most cases it is best to make 
a statement of the leading facts, and a few statements about the specific 
situations to give an idea of the kinds of animals that are characteristic 
or common there. It should be noted also that the most characteristic 
animals are often not generally known and are in some cases rare. 
The scientific names of characteristic and common animals are 
included, not so much for geographers at present, as to form a basis for 
further work and comparison by zodlogists and zoégeographers. Where 
given in the form of tables they present the actual scientific background 
for the facts here stated. Much greater detail would be needed for a 
full zodlogical treatment. Scientific names are usually used where the 
common names apply to many species. ‘The names of authors of species 
are added in the text and description of figures only where they do not 
