54 GREAT NORTHERN DIVER OR LOON. 
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 ex- 
tremely narrow, and extending beyond the middle, the dorsal line 
straight and sloping upwards to the point, the ridge convex and nar- 
row, 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 de- 
pressed, of an elliptical form viewed from above. Wings small. Feet 
short, rather large, placed very far back; tibia almost entirely con- 
cealed ; tarsus short, exceedingly compressed, sharp-edged before and 
behind, covered all over with reticulated angular scales ; hind toe ex- 
tremely 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 narrow scutella, the 
second toe with a free two-lobed membrane ; claws very small, depres- 
sed, blunt. 
Plumage short and dense; of the head and neck very short, and 
blended ; of the lower parts blended, short, with slight gloss; of the 
upper compact, glossy; the feathers in general oblong, those of the 
upper parts with the extremity abrupt. Wings proportionally very 
small and narrow, curved ; primaries strong, tapering, the first longest, 
the second almost as long, the rest rapidly graduated ; secondaries 
broad, and rounded. Tail extremely short, rounded, of twenty feathers. 
Bill black. Iris deep bright red. Feet, tarsi, and toes, of a livid 
greyish-blue, their inner sides tinged with pale yellowish flesh-colour ; 
claws black, lighter at the base ; webs brownish-black, lighter in the 
middle. Head and neck dark greenish-blue, with purple reflections. 
On the throat a small transverse patch of white, longitudinally striated 
with dusky ; about the middle of the neck, two large patches of the 
same, separated in front to the distance of an inch, behind continuous, 
but when the feathers are laid close, appearing as if separated by a 
longitudinal dark band about half an inch in breadth. The under parts 
glossy white, excepting the feathers on the sides under the wing, which 
are black, each with two, three, or four elliptical white spots, a faint 
