244 



Dwight, Larus hyperboreus. 

 W/rvq 



r Auk 



[April 



? $> 



+ 1SO 



- mm 



TAIL 



TA/fSUS 



9- * 



£ £ <? <? 



CULM EN (exposed) 



DEPTH of BILL 

 AT BASE 



/ ■ hyperboreus . 

 / = %a rro v/anu<s " 

 / - Oberhoiserls measurements. 



Fig. 1, Diagrams showing relative measurements in millimeters of 31 adult 

 specimens of Larus hyperboreus and its alleged race. Top line shows actual length 

 in largest birds, middle line shows average, and bottom line shows smallest of the 

 series. 



