140 



PATAGONIAN EXPEDITIONS : ZOOLOGY. 



GENERAL DESCRIPTION. 



Size. Adult Male. Total length, about 18 inches. 

 Wing, 12.5 to 13 inches. 



Tail, central rectrices, 5.1 inches; lateral rectrices, 4.15 inches. 

 Bill, 2.1 inches. 

 Tarsus, 1.8 inch. 



Color. Adult Male. General color above clear pearl grey, below 

 white. The pearl grey shading into the white without abrupt demarcation. 



FIG. 83. FIG. 84. 



Prioctlla glacialoides. Profile of head. 

 From material in the British Museum. l / 2 

 natural size. 



Priocella glacialoides. Head from above. 

 From material in the British Museum. ^ 

 natural size. 



Head : Top of head and crown pale pearl grey, lighter than on the 

 back. Forehead white, grey of top of head shading into white on the 

 sides of face and cheeks. A dusky spot in front of the eye. 



Neck: Above pale pearl grey like the crown shading into white on the 

 sides. Lower neck, throat and chin white. 



Back : Uniform pearl grey, of a darker shade than on the crown and 

 upper neck. Upper tail coverts like back. 



Wing : Upper coverts, pearl grey. Primaries, exposed portion greyish 

 black, the exposed portion of the shafts black : concealed portion yellow- 

 ish white at the base. The inner webs are pearly white nearly to the tip 

 of each feather. Secondaries, slaty black on their outer webs and white 

 on their inner webs. Tertials, pearl grey like the back. Feathers of the 

 edge of the wing greyish slate. 



