52 MEMOIR OF LAMARCK. 



in consequence of Baron Cuvier's observations on 

 their circulating organs and the colour of their 

 blood, which resembles that of the vertebrate races. 

 Two other classes were created, in his " Philosophi- 

 cal Zoology," viz. the infusoria and the centripedes ; 

 and in this work also he first deviated from the 

 ordinary practice of commencing the arrangement 

 with the most perfectly organized, the inverse order 

 being more in accordance with his theoretical views, 

 which assumed a gradual progression in the compo- 

 sition of animal organs, proceeding from the most 

 simple to the most complex. 



It was in a small volume, entitled " An Extract 

 from the Zoological Course in the Museum of Na- 

 tural History, on the invertebrate Animals," &c. 

 published in 1812, that he first presented his general 

 distribution of animals into three grand divisions, 

 apathetic, sentient, and intelligent. This plan he 

 made the foundation of his great work, and the 

 method in which he applied it, as well as his ideas 

 regarding the constitution of the different classes, 

 and their relation to each other, will be understood 

 from the subjoined table. 



