THE BAY OF BISCAY. 183 



of the most characteristic tendencies of the group. 

 Considered in this respect, they are only Annelids 

 which possess a greater degree of perfection than the 

 others. 



This remarkable independence of the different 

 parts of the body of the same animal, and the strange 

 diffusion of the faculties of perception and of a 

 reasoning will through all parts of the nervous sys- 

 tem, are not exclusively exhibited by the Annelids. 

 The same thing is to be met with in insects, animals 

 whose organic complication exceeds in many respects 

 even that of man himself.* 



The experiments of Duges leave no doubt on this 

 point. If you imitate this skilful and lamented na- 

 turalist, and if you successively remove from a 

 Praying Mantis the head and the posterior part of 

 the body, the prothorax which remains will live for 

 more than an hour, although it now only contains a 

 single ganglion. If you attempt to seize it, you will 

 find that the aggressive feet of the animal will 

 be directed towards your fingers, into which it will 

 bury the powerful hooks with which they are armed. 

 The abdominal ganglion, which alone animates the 

 ring, has therefore /<?# the fingers which pressed the 

 segment ; it has recognised the point that was pressed 

 by a foreign body ; it wishes to free itself from this 

 constraint, and hence it directs towards the point 

 that has been attacked its natural arms, and co-ordi- 



* Lyonnet, in his admirable Anatomic de la Chenille du Saule, 

 and M. Strauss-Durckheim, in his Anatomic du Hanneton, have 

 placed this general result beyond all doubt 



N 4 



