PERIOD OF CUVIER. 315 



tive, and Intelligent animals, are an imitation of the four 

 branches of Cuvier; but, far from resting upon such a 

 definite idea as the divisions of Cuvier, which involve a 

 special plan of structure, they are founded upon the 

 assumption that the psychical faculties of animals present 

 a serial gradation, which, when applied as a principle of 

 classification, is certainly not admissible. To say that 

 neither Infusoria, nor Polypi, nor Kadiata, nor Tunicata, 

 nor Worms feel, is certainly a very erroneous assertion. 

 They manifest sensations quite as distinctly as many of 

 the animals included in the second type, which are called 

 Sensitive. And as to the other assertion, that they move 

 only by their excited irritability, we need only watch the 

 Starfishes to be satisfied that their motions are deter- 

 mined by internal impulses, and not by external excita- 

 tion. Modern investigations have shown that most of 

 them have a nervous system, and many even organs of 

 the senses. 



The Sensitive animals are distinguished from the third 

 type, the Intelligent animals, by the character of their 

 sensations. It is stated, in respect to the Sensitive ani- 

 mals, that they obtain from their sensations only percep- 

 tions of objects, a sort of simple ideas which they are 

 unable to combine so as to derive from them complex 

 ones, while the Intelligent animals are said to obtain 

 ideas which they may preserve, and to perform with 

 them, operations by which they arrive at new ideas. They 

 are said to be Intelligent. Even now, fifty years after 

 Lamarck made those assertions, I doubt whether it is 

 possible to distinguish in that way between the sensa- 

 tions of the Fishes, for instance, and those of the Cepha- 

 lopods. It is true, the structures of the animals called 

 Sensitive and Intelligent by Lamarck differ greatly, but 



