ICELAND OR JER FALCON. 477 
The plumage is compact, and the feathers are of the same form in both 
birds, but those of the head are a little broader in the Iceland bird. 
On the whole, however, no differences are observable beyond what 
might be expected between a young and an old individual of the same 
species. The colouring of the Iceland bird, however, is very different. 
The bill is very pale blue, the extremity of the upper mandible black, 
that of the lower yellowish; the eyes greyish-black ; the cere, superci- 
liary ridge, edges of eyelids, tarsi and toes, pale yellow ; the eyelids pale 
blue ; the claws black. The plumage is pure white, but all the feathers 
of the back and rump, the scapulars, the wing-coverts, and the se- 
condary quills, have near their extremity a brownish-black spot, ge- 
nerally arrow-shaped. ‘The anterior feathers of the back have, more- 
over, a black streak on the shaft, which on those farther back be- 
comes larger and lanceolate, and on the rump is accompanied by a third 
spot ; the larger coverts and secondary quills have also three or more 
spots, and the primary quills have seven spots or partial bars toward 
their extremity, besides a large subterminal black space, their tips 
however being white. On the inner margin of the two middle tail- 
feathers are eight, and on the outer four dusky spots, and their shafts 
are also dusky, as are those of all the quills on their upper surface. 
There are also a few slight lanceolate dark spots on the sides of the 
body, and on the tibial feathers. 
Length to end of tail 233 inches, to end of wings 214, to end of 
claws 183, to carpal joint 53; extent of wings 514; breadth of gape 
11; wing from flexure 17; tail 92; bill along the ridge 1,5; tarsus 
274; hind toe 1,1,, its claw 1,°,; middle toe 27, its claw (worn) 43. 
Weight 2 lb., it being much emaciated. 
The tongue, a. is 103 twelfths long, fleshy, deeply emarginate at the 
base, having on its upper surface numerous orifices of mucous crypts, 
towards the end narrowed, deeply concave, horny, with the extremity 
rounded and very slightly emarginate. The cesophagus, bede, is 74 inches 
long, wide, dilated into a large crop, cd, lying on the right side ; the pro- 
_ ventriculus, / is $ inch in diameter, with a belt of oblong glandules, ar- 
ranged into four very prominent longitudinal ridges, with deep grooves be- 
tweenthem. The stomach, fg 4, is round, compressed, 13 inch in length, 
1 inch 5 twelfths in breadth ; its muscular coat thin, composed of large 
fasciculi, not arranged into distinct muscles ; its inner coat soft, with- 
