THE FOSSIL AVIFAUNA OF THE 
105 
At the present time this species is abundant in many parts of Oregon. 
Cope collection : Equus Beds, Oregon. 
AlX SPONS.X. 
A perfect humerus, nunierus coracoids, and several other Ixnies represent 
this Duck in the collection. Upon comparison with a skeleton of the s|>ecies in 
the U. S. National Museum (No. 18,612) they all agree very closely in their char- 
acters, and in all probability the Aix of the Pliocene Avas the same form of bird, 
in so far as its osteology was concerned, as we now have in our avifauna. Length 
of humerus 72 millimetres. Length of carpo-metacarpus 47 millimetres. The cora- 
coid, somewhat compressed in the autero-posterior direction, measures in length 44 
millimetres. The bones of the pectoral limb seem to be slightly slenderer than in 
fossil specimens, but it may- be due to individual variation, and the skeleton of 
the existing species at my hand may have been taken from a I’ohust bird. 
Equus Beds of Oregon (Silver Lake) ; Cope collection. 
Aythya maeila neaectioa ? 
I find in the collection a humerus, an ulna, and two coracoids which evidently 
belonged to an Aythya. They have been compared by me with a skeleton of the 
Canvasback Duck [Aythya vallisncria) \ also Avith a skeleton of a Hedhead (.7. 
americana) ; and also with A. affinis and A. coUaris. The specimens are too small 
for vallisneria and americana, and too large for affinis or collaris. 1 have no 
skeleton of A. marila nearctica, but know it to he a larger bird than either A. 
affinis or A. collaris, and so for the present I refer the above named 8i)ecimens to 
the American Scaup Duck. It is as Avell to remark that both the humerus and the 
coracoids appear to have belonged to a subadult individual, as they exhibit tlie 
peculiar gray tint and the very fine granulated appearance of the surface. Lmgth 
of humerus 90 millimetres ; greatest breadth of proximal extremity 20 millimet ivs; 
greatest breadth of distal end 12 millimetres. 1 am not inclined to regard thi.« a.s 
an extinct species of Aythya. 
Cope collection: Pliocene (Equus Bods of Silver Lake) ; Oregon. 
Glaucionetta islandica. 
This species was very abundant during the Pliocene in the Silver Taike Kegion ; 
perhaps the most abundant Duck. Professor Cope’s collection has in it 26 siH-ciinen.s 
of the humerus of Glaucio 7 ietta islandica, ten of which are as perfect a.s though 
iust taken from recently killed individuals. There are also numerous other Ik.iu-s, 
but no part whatever of the trunk skeleton. All these fossil hones agive m the 
minutest details with the corresponding bones of specimens of the species as they 
exist to-day. To establish this fact, I compared them all carefully with skeletons 
of Glaucionetta islandica contained in my own private collection. Luigth of 
humerus 84 millimetres; length of ulna 74 millimetres ; lengtl, of cariHHiietacarpus 
51 millimetres, (absolutely identical in fossil and existing species). 
Cope collection : Equus Beds of Silver Lake, Oregon. 
