RECORDS OF MEETINGS 255 



processus. The stajDes is of younger tissue than tlie other ossicles, and is 

 still connected by an "interhyale" to the dorsal end of the hyoid cartilage. 



Mr. Nichols stated that his paper deals with vertebrate variants 

 (forms or species of animals more or less related but differing from one 

 another) which, although geographical, are not direct or obvious re- 

 sponses to the environment. 



Several types of variant are defined. Eepresentative forms occupy- 

 ing adjacent regions are designated as adjacent races or species; forms 

 intermediate in structure between adjacent forms and occupying terri- 

 tory remote from them as foreign intermediates ; related forms occupy- 

 ing the same territory and contrasted in superficial characters as com- 

 plements; forms separated geogTaphically and showing greater resem- 

 blance (not induced by environmental adaptation) than their degree of 

 relationship would presuppose, as outcrops. 



The hypothesis was advanced that, probably on account of competition, 

 closely related forms are antagonistic. That is when in touch geograph- 

 ically they tend to force one another apart in superficial characters. If 

 this hypothesis, Avhich seems to fit into certain known facts extremely 

 well, be accepted, it involves a centrifugal force in evolution opposed to 

 the centripetal tendencies of blood relationship. 



It is the main theme of the paper to advance the concept of these two 

 forces as the fundamental framework of evolutionary control, the helm 

 which is swayed by natural selection or other forces. 



The Section then adjourned. 



William K. Geegory, 



Secretary. 



SECTION OP GEOLOGY AND MINEKALOGY 



21 Febeuaey, 1916 



Section met at 8 :20 p. m., Vice-President Douglas W. Johnson pre- 

 siding. 



The minutes of the last meeting of the Section were read and ap- 

 proved. 



The following program was presented : 



S. H. Knight, Climatic Conditions in Soutpiern Wyoming 



DuEiNG Deposition of the "Red Beds.'' 



Charles P. Berkey, Unstable Conditions Exhibited by some oe the 

 Rock Poundations of the Hudson Valley. 



