384 NEW YORK STATE MUSEUM 



8 Analysis of progressive development in septal structure of the goni- 

 atites indicates that species in Timan, New York and Germany having 

 external differentials closely approximate, are simplest in septal expression 

 in Timan, more progressed in New York and attain extreme specialization 

 in this respect in Germany. Interpreting this as an indication of progres- 

 sive modification during migration we find herein additional evidence of 

 dispersion from Timan eastward to New York and from New York east- 

 ward to Europe. 



