Fundamental Types of Organization. 79 



paralion into cesophagus, stomach and intestine. The latter, 

 moreover, is not as in the former attached to a hver. Its pos- 

 terior extremity certainly opens as in them above the generative 

 organs. But their proper tongue is not situated below but 

 above the entrance of the pharynx. When, however, we speak 

 of development from a common primitive form, and the combi- 

 nation of one form with another, it is not to be understood that 

 these developments and combinations follow the same rules as 

 pairing and generation in the presently existing nature. 



S. No conclusion can be drawn from the absence of an or- 

 gan, regarding its purpose, nor vice versa. An example of 

 this is furnished by the auditory ossicula of fish, discovered by 

 Weber, which are evidently parts of the vertebral column, al- 

 though attached to the organ of hearing, which in other ani- 

 mals is quite unconnected with the column. Another instance 

 is in the mandibules of the Crustacea and insects. These organs 

 have the same function as the maxillae of the vertebrata. But 

 they do not like the latter move in a plane parallel to the axis 

 of the body, but in one at right angles to this axis. In many 

 Crustacea, moreover, they perform the function of legs. On 

 the contrary, the organs of these two classes which move in a 

 plane similar to that of the jaws of the higher animals, viz. the 

 upper and under lips, have a totally different function. 



To return to our proper subject, the distribution of living ex- 

 istences ; according to our principles of considering life and the 

 intellectual faculties as one and the same, we may be allowed to 

 consider the organs through the medium of which the activity 

 of the living principle passes to the other bodies in the animal 

 kingdom, as those with whose perfection the structure of the 

 other parts must stand in connection. And the more intimate 

 the connection the higher the gradation of life. These organs 

 are the brain, spinal cord, and nerves. 



The presence or absence of these organs, as characterising 

 the existence or non-existence of voluntary motion, has always 

 been considered as the basis of the two grand divisions of living 

 nature into animals and plants. No nerves, it is true, can be 

 detected in the simpler animals ; but as they have been disov 

 vered in some to which they were formerly refused, and as these 

 species are intimately connected with those in which they have 



