GREAT NORTHERN DIVER. 291 



for the marrow being very small. All the bones of this specimen were 

 presented to Mr. Thomas Allis, of the Friends' Retreat, near York. 



My friend Captain James Clark Ross, of the Royal Navy of England, 

 °nce placed at my disposal a specimen of the Loon procured in a very high 

 latitude, and which, having closely inspected it, I found to differ from the 

 one represented in the plate, only in having the point of the bill slightly 

 elevated or recurved, and of a fine yellow tint. Dr. Richardson informed 

 me that, on one of his arduous northern journeys, he saw a very large and 

 handsomely crested Diver, which, although somewhat prematurely, I pro- 

 pose honouring with the name of Colymbus Richardsoni. 



Great Northern Diver or Loon, Wils. Amer. Orn., vol. ix. 



Colymbds glacialis, Bonap. Syn., p. 420. 



Colymbus glacialis, Great Northern Diver, Swains, and Rich. F. Bor. Amer., vol. ii. 



p. 474. 

 Loon or Great Northern Diver, Nutt. Man., vol. ii. p. 513. 

 Great Northern Diver or Loon, Colymbus glacialis. Aud. Orn. Biog., vol. iv. p. 43. 



Adult, 32 J, 57^-. Young Male, in winter, 3H, 54 £, 



During winter dispersed over the United States, in Texas, as well as along 

 the coasts of the Atlantic, and the north-west. Breeds from Massachusetts 

 northward to very high latitudes. Common. 



Adult Male. 



Bill as long as the head, straight, stout, much compressed, tapering to a 

 point. Upper mandible with the dorsal line descending and slightly convex 

 towards the end, the ridge convex, narrowed towards the point, the sides 

 convex beyond the nostrils, the edges sharp and considerably inflected, the 

 tip narrow and sharpish. Nasal groove short, nostrils basal, linear, direct, 

 pervious. Lower mandible with the angle extremely narrow, and extending 

 beyond the middle, the dorsal line straight and sloping upwards to the point, 

 the ridge convex and narrow, the edges sharp and involute; the tip 

 attenuated. 



Head of moderate size, oblong, narrowed before. Neck rather long and 

 thick. Eyes of moderate size. Body elongated, much depressed, of an 

 elliptical form viewed from above. Wings small. Feet short, rather large, 

 placed very far back; tibia almost entirely concealed; tarsus short, exceed- 

 ingly compressed, sharp-edged before and behind, covered all over with 

 reticulated angular scales; hind toe extremely small, connected with the 

 second by a very small membrane; the anterior toes united by articulated 

 membranes, the fourth or outer longest, the third a little shorter, the second 

 considerably shorter than the third, all covered above with very numerous 



