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THE INDUCTIONS OF BIOLOGY. 



But though Cuvier emancipated himself from the concep- 

 tion of a serial progression throughout the Animal Kingdom, 

 sundry of his contemporaries and successors remained fet- 

 tered by the old error. Less regardful of the differently- 

 combined sets of attributes distinguishing the different sub- 

 kingdoms, and swayed by the belief in a progressive develop- 

 ment which was erroneously supposed to imply a linear ar- 

 rangement of animals, they persisted in thrusting organic 

 forms into a quite unnatural order. The following classifi- 

 cation of Lamarck illustrates this. 



INVERTEBRATA. 



I. APATHETIC ANIMALS. 



Cl. 1. Infusoria. 

 Cl. 2. Polypi. 

 Cl. 3. Radiaria. 

 Cl. 4. Tunicata. 

 Cl. 5. Vermes. 



II. SENSITIVE ANIMALS. 



Cl. 6. Insects. 



Cl. 7. Arachnids. 



Cl. 8. Crustacea. 



Cl. 9. Annelids. 



Cl. 10. Cirripeds. 



Cl. 11. Conchifera. 



Cl. 12. Mollusks. 



Do not feel, and move only by their 

 excited irritability. No brain, no 

 elongated medullary mass ; no senses ; 

 forms varied ; rarely articulations.! 



Feel, but obtain from their sensa- 

 tions only perceptions of objects, a 

 sort of simple ideas, which [they are 

 unable to combine to obtain complex 

 ones. No vertebral column ; a brain 

 and mostly an elongated medullary 

 mass ; some distinct senses ; muscles 

 attached under the skin; form sym- 

 metrical, the parts being in pairs. 



VERTEBRATA. 



III. INTELLIGENT ANIMALS. 

 Cl. 13. Fishes. 

 Cl. 14. Reptiles. 

 Cl. 15. Birds. 

 Cl. 16. Mammalia. 



Feel ; acquire preservable ideas ; 

 perform with them operations by which 

 they obtain others ; are intelligent in 

 different degrees. A vertebral column ; 

 a brain and a spinal marrow ; distinct 

 senses ; the muscles attached to the 

 internal skeleton; form symmetrical, 

 the parts being in pairs. 



Passing over sundry classifications in which the serial 

 arrangement dictated by the notion of ascending complexity, 

 is variously modified by the recognition of conspicuous 

 anatomical facts, we come to classifications which recognize 



