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 "Philosophical 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 composition 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 Natural 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.
