14 



EVOLUTION AND ANIMAL LIFE 



The number of species actually existing is far beyond ordi- 

 nary conception. The earliest serious attempt to catalogue the 

 species of animals and plants was made by Linnaeus. In the 

 tenth edition of his '' Systema Nature ^' in 1758, in the 823 pages 



Fig. 3. — Brittle or serpent stars — species undetermined. (Natural size,) 



devoted to animals, he describes and names some four thousand 

 different kinds. Great as this number seemed, Linnaeus ven- 

 tured to suggest that probably his pages did not include half of 

 those kinds of animals actually existing. 



To-day our records contain descriptions of more than one 

 hundred and fifty times as many kinds of animals as were known 

 to Linnaeus and all his predecessors and all his associates of a 

 century and a half ago. Each year, since 1864, there has been 

 published in London a volume called the "Zoological Record.'^ 

 Each of the volumes — larger than the whole " Systema Naturae" 

 ■ — contains the names of the animals new to science which have 

 been added to the system in the year of which it treats. In the 



