66 ZOOLOGICAL PHILOSOPHY 



Justicia, Convallaria, and many others ; and now botanists are re- 

 establishing the genera which Linnaeus had destroyed. 



Finally last year (in my course of 1807) I established among in- 

 vertebrate animals a new class — the tenth — that of infusorians ; because 

 after a careful examination of the characters of these imperfect animals,, 

 I was convinced that I had been wrong to place them with the polyps. 



Thus, by continuing to collect facts from observation and from the 

 rapid progress of comparative anatomy, I instituted successively 

 the various classes which now compose my arrangement of inverte- 

 brate animals. These classes, to the number of ten, are arranged 

 in order from the most complex to the simplest as usual, viz. : 



Classes of Invertebrate Animals. 



Molluscs. Insects. 



Cirrhipedes. Worms. 



Annelids. Radiarians. 



Crustaceans. Polyps. 



Arachnids. Infusorians. 



I shall show, when I come to deal with each of these classes, that 

 they constitute necessary groups, since they are based upon a study 

 of organisation ; and that although races may, nay must, exist near 

 the boundaries, half way between two classes, yet these groups are the 

 best attainable by artifice. They will therefore have to be recognised, 

 so long as the interest of science is our chief concern. 



By adding to these ten classes into which the invertebrates are 

 divided, the four classes of vertebrate animals identified and deter- 

 mined by Linnaeus, we shall have a classification of all known animals 

 into the following fourteen classes, set out once more in the opposite 

 order to that of nature. 



1. Mammals. 



2. Birds. 



3. Reptiles. 



4. Fishes. 



5. Molluscs. 



6. Cirrhipedes. 



7. Annelids. 



8. Crustaceans. 



9. Arachnids. 



10. Insects. 



11. Worms. 



12. Radiarians. 



13. Polyps. 



14. Infusorians, 



Vertebrate animals. 



• Invertebrate animals. 



