THE PROBLEM 9 



example, a high degree of order is apparent in relation 

 to an axis drawn through the center of the body vertical 

 to the plane in which the arms extend. Centering about 

 this axis is an order referable to radii centering in this 

 axis, and again the order in each arm is referable to a 

 plane passed through the radius of each arm and the 

 central axis of the body. In a bilaterally symmetrical 

 individual, such as man and many animals, the order 

 can be referred to three axes — longitudinal, transverse, 

 and dorso-ventral — at right angles to each other, or 

 perhaps better to a longitudinal axis, and two planes, 

 transverse and ventro-dorsal, passed at right angles to 

 each other through this longitudinal axis. 



These axes and planes drawn through the individual 

 as a whole represent merely the general plan of orderly 

 arrangement. Geometrical relations are also distin- 

 guishable in the order of various parts and organs, and 

 these relations do not necessarily coincide in direction 

 with the geometrical scheme of the whole individual 

 but differ from it in all conceivable ways. Evidently 

 the geometrical relations of order in the organic indi- 

 vidual, particularly where the structure is complex, are 

 by no means as simple as the general scheme might seem 

 to indicate. 



The reason for making a distinction between polarity 

 and symmetry lies in the fact that in most axiate 

 individuals one axis, the polar axis, is distinguishable 

 as the chief or major axis of the body. In the direction 

 of this axis the specialization and differentiation are 

 most marked and the order in this direction is usually 

 more conspicuous or more stable and commonly appears 

 earlier than that in other directions. This axis is also 



