Oberholser — The Status of Larus hyperboreus barrovianus. 175 



exposed culmen and ours. As his figure shows, his measure- 

 ment is taken in a straight line from the feathers of the forehead 

 to a point directly above the tip of the bill; while ours, as that 

 of ornithologists generally, is the chord of exposed culmen, a 

 considerably greater dimension, particularly in the case of a 

 large bird, and, of course, not comparable with the other. 



The above differences between Larus hyperboreus barrovi- 

 anus and Larus hyperboreus hyperboreus are shown separately 

 as well as collectively by the series in every collection the 

 writer has examined, a list of which will be found in our original 

 article. 1 Furthermore, all the ornithologists, in Cambridge, 

 Mass., Philadelphia, Pa., and Washington, D. C, to whom we 

 have pointed out the characters of Larus hyperboreus barrovianus 

 agree with us in considering it a readily recognizable sub- 

 species. 



1 The Auk, XXXV, No. 4, October, 1918, p. 468. 



