SM ALLEY: PACIFIC EIDER IN BRITISH WATERS. 73 



Size. — S. v-nigrum is much larger, a bigger and heavier 



duck in every way. 



Beak. — In 8. v-nigrum, the colour is deej) orange, which 



is retained many years after death, and probably 



permanently. 



Frontal Processes. — The lateral and forward extensions 



of the frontal feathers in S. v-nigrum do not reach 



the posterior end of the nostrils, and have rounded 



instead of acute terminations. The extension of 



feathers on the chin extends beyond that on the 



sides of the bill, the reverse being the case in 



8. m,ollissima. 



The Y-Mark. — In >S'. v-nigrum it is bold, with sharply cut 



edges ; is 3*3 inches from apex to base, and '3o to '4 



inch in thickness, and is of the same velvety black shade 



as the feathers on the occiput, whereas the Y-mark in 



8. moUissima is small, indistinct, with ragged edges, 



and " mouse-colour " would better define the shade 



than "black." 



The Green Patch on Sides op Head. — In 8. v-nigrum 



the green encroaches on the white on the sides 



of the head, and extends beyond the eye. In 



8. mollissima it does 7iot encroach on the white on 



sides of head. 



Although Mr. Stubbs is quite as convinced as I am that 



the Oldham specimen is not 8. v-nigrum, yet he is not so 



certain that it is *S'. mollissima. In a letter to me dated 



March 23rd, 1907, he writes: "It would be as well to 



remember that our Eider (i.e. ' the Oldham bird '), if we 



leave out of consideration the black Y-mark, resembles, 



in its yellow bill and very falcate tertials (far more falcate 



than those of any other specimen of the genus I have seen), 



the variety known as the Northern Eider, 8. m. borealis 



of Ridge way." 



I do not consider 8. m. borealis a good species, and can 

 find no single point in which the two differ, and certainly 

 no well-defined and constant difference sufficient to 

 warrant the two being separated even as subspecies. A 



