568 PUFFINIDA 
and under parts, are pure white, the other in which they 
are shaded grey. In Iceland, and on the western side of 
Davis Strait and Baffin Bay, the latter is chiefly to be found, 
while at Ovifak in Greenland, the former abounds. Both 
forms occur round Spitzbergen, but the grey-plumaged birds 
are in the majority. FF. rodgersi, with only a light phase, 
and with the back and rump interspersed with white, 
inhabits Behring Sea, and F’. glupischa, with pale-coloured 
nasal-tubes, the North Pacific. he latter has a light and 
a dark phase of plumage (Saunders). 
