226 Proceedings of the Royal Physical Society. 
ligamenta alaria are homologous with the transverse liga- 
ment. 
The large portion of the cup on the anterior aspect of the 
chelonian atlas, which is formed hy the expanded inferior 
extremities of the arch, illustrates very well the unity of 
plan upon which the articular surfaces of the atlas are 
formed in animals having one occix-)ital condyle, and those 
which have two. This will be seen by comparing the wood- 
cuts above. 
When, in the human subject, a process of bone passes up 
from the arch of the atlas, to meet the superior articular 
surface, and convert the groove for the nerve and vertebral 
artery into a foramen, the process in question is a true 
oblique process. If, in addition, we were to imagine the 
tip of the transverse process thickened and projecting up- 
wards to meet the superior articular surface, we should then 
have presented to us the condition of parts found in the pig 
and the sheep. 
IV. Ornithological Notes. Bj John Alexander Smith, M.D. 
(Specimens exhibited.) 
(1.) Falco islandicus, (Lath). The Gyrfalcon. 
This specimen of Gyrfalcon was killed about the middle 
of last October by James Maclean, gamekeeper to Sir 
John Orde, on his property near Loch Maddy, in North 
TJist. Tne bird is probably a young male, and a very 
fine specimen of this extremely rare and occasional visitor, 
— no instance of its breeding in Scotland, he believed, was 
on record. It measured in length 22J inches ; the wing, 
from flexure to point of primaries, 15 inches. The head 
white, with longitudinal stripes of brown ; the upper parts 
of body brown, tinged with grey ; the feathers partially 
edged and spotted on the margins with white. Below 
white, with longitudinal , spots of brown ; the flanks white, 
broadly dashed with brown. In the wings, the second pri- 
mary is the longest, the first and third being nearly equal. 
Tail brown, barred with white, the white mottled with 
brown. 
Another specimen of this falcon was killed by Maclean 
