28-4 BULLETIN OF THE MUSEUM OF COMPARATIVE ZOOLOGY. 



be taken into account in comparing the plants of the United States 

 Coal measures with those of Canada. From this you cannot derive 

 any reliable conclusion. Pecopteris plmnosa in the Devonian would 

 appear to me quite an anomaly, but not more so than to see it in 

 the lower Permian." 



1 suppose that everybody will agree that the plant in question should 

 be studied and determined with the utmost care to avoid any further 

 doubt concerning the age of those interesting insects. 



