592 GAVIA ATRICILLA. 



to characterize as tlic Dark-headed Mews, arc of necessity 

 liable to lead into error. The normal state of the six outer 

 quills is to have white tips, except the outer two, or some- 

 times three, but as these tips arc small, they are liable to be 

 soon partially or entirely obliterated by the abrasion of their 

 points. 



