284 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 plumosa in the Devonian would 
appear to me quite an anomaly, but not more so than to see it in 
the lower Permian.” 
I 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. 
