160 THE ORGANIZATION 



progressive idea of the development of the nervous system, and 

 the gradual differentiation of the digestive and circulatory sys- 

 tems, throughout all animals ; making the animal kingdom one 

 symbolical animal) passing in its development from the lowest to 

 the highest expressions of life. 



Thus in the Protozoan stage, (see diagrams, page 122,) which 

 is the lowest, the nervous system, although formless and scat- 

 tered, holds a certain position in reference to the other organs. 

 In the Zoophyte stage the nervous system is more collected, and 

 arranged in reference to right and left, and above and below. 

 In the Molluscan phase this system becomes more concentrated 

 toward the side opposite to that on which the heart is placed. 

 In the Articulate state the concentration is carried out still fur- 

 ther ; and finally, in the Vertebrate condition the nervous system 

 attains its highest confluence toward the median line, and in its 

 tendency toward the head ; as had already been foreshadowed 

 in the highest Mollusca, i. e., cuttle-fishes, and in Insecta. 



And now let us turn from these general relations to a consid- 

 eration of those special kinds which characterize each grand 

 division by itself. In order to make these special type rela- 

 tions clear to your eyes, I must use a different set of illustrations, 

 as I do not wish to superimpose on these ideal figures of the 

 progress of the typical animal -development anything which 

 may obscure the main idea. It is best that it should stand alone 

 for the purpose of further illustration when I come to the discus- 

 sion of the typical idea of each separate grand division. 



I will commence with the lowest type of undoubted animals, 

 the Protozoa, and proceed upward, so as to show how the two 

 ideas ; e. g., bilaterality, and the type of division, are related, and 

 how the type of each grand division is superimposed upon the 

 symbolic, bilateral idea. 



Protozoa. The type of this division is found in its relation to 

 a spiral; it is the oblique or spiral type. If you will call to mind 

 now, by the help of these figures of Stentor, (figs. 30 to 33, pp. 

 62, 63,) what I have told you about its structure, I think you will 

 readily understand me when I speak of the oblique or spiral type 



