Orthoplasy with Correlated Variation 207 



vocal organs are correlated with the loosely attached upper 

 mandible. 



Again, suppose we take such a generalized function as 

 imitation. It is not shut down to a single particular chan- 

 nel of expression, but applies equally to a great variety of 

 alternative and possible functions which the imitative 

 creature may be at any time led to exercise. This ten- 

 dency to imitate screens many incomplete functions, and 

 thus serves very essential utilities in life history. But this 

 does not mean that in each case variations are fostered 

 only toward the congenital performance of the function 

 in just the same way that the imitative performance se- 

 cured it. On the contrary, as is said on an earlier page, 

 and as has been maintained by Professor Groos, the imita- 

 tive functions act in many cases to develop the intelligence, 

 to enable the creatures to do many things by a type of 

 action which discourages evolution by coincident variation 

 in these directions, and encourages variation of the opposite 

 sort, that, namely, toward greater plasticity and intelli- 

 gence. Here the saving utility of individual accommoda- 

 tion is exercised in the way postulated by organic selection : 

 it screens the organism and utilizes a partially congenital 

 and quasi-reflex mechanism; but its racial utiUty in con- 

 nection with many functions seems to be just the reverse 

 of the selection of coincident variations. Yet in other cases, 

 indeed, as is maintained in an earlier discussion of the 

 subject (Chap. VI., above), its results are strictly in accord 

 with the theory of the development of coincident variations. 



Apparently — in view of these illustrations and others 

 which might be cited ^ — we may look to the accommodations 



1 As, for example, that of the evolution of mammalian teeth, mentioned by 

 Professor Osborn (quoted in Appendix A, I.). If, as is suggested in App. A, I., 



