104 RAMBLES OF A NATURALIST. 



inferior types, they are naturally induced to reject 

 as foreign to their primitive types the greater number 

 of the lower derivatives presented to their notice. 

 This fact explains how Cuvier*, notwithstanding his 

 marvellous genius, should so completely have mis- 

 understood certain relations, as to incorporate certain 

 Mollusca and Articulata among the Zoophytes, with- 

 out perceiving the incongruity of such an association. 

 The case is different with the groups which belong 

 to the primordial type of the Invertebrata. For the 

 three great divisions of the Mollusca, Articulata, and 

 Radiata present in each of their classes fundamental 

 differences, and characters which occasionally present 

 considerable opposition to one another. At the head 

 of each of these series we find animals in which the 

 division of labour is carried quite as far perhaps as 

 in the Vertebrata themselves.! In proportion, how- 

 ever, as we deviate from these culminating points, 

 the functions become more circumscribed, or merge 



* [A sketcli of the Life and Labours of Cuvier is given in the 

 Appendix, Note IX.] 



f We may cite the Insects as an illustration. To form an 

 adequate idea of the complicated organism of these animals, we 

 need only examine Lyonnet's plates on the Anatomy of the 

 Caterpillar of the Goat Moth (the Cossus Ugniperda), and those by 

 M. Strauss-Durckheim, on the Anatomy of the Cockchafer. It 

 is sufficient to remark that the former of these observers has 

 counted 1647 muscles in the body and 228 in the head of the 

 caterpillar, which would give a total of 1875 distinct muscles serving 

 for the voluntary movements of the caterpillar, whilst in man there 

 are not more than 529. To these 1875 voluntary muscles we must 

 add, according to Lyonnet, 2186 muscles belonging to the digestive 

 apparatus, which will give us a total of 4061 for the entire number 

 of muscles in the body of a caterpillar. 



