Lucas o?i the Os Prominens . 
87 
ensis , B. virginianus , Scops brasilictnus , <25/0, Nyctea scan- 
diaca , Ninox albigulare , ALs 7 <? Syrnium nebulosum , and 
■S'. uralense. It is not present in Strix Jlammea or S’. perlata , 
and should it prove to be present in other genera of the Buboni- 
dce than those noted above, it may serve as an additional, though 
trivial, point of distinction between the families Bubonidce and 
Strigidce. 
Left wing of Bubo ving ini anus, from below (reduced one third) . 
r, radius; u, ulna; c, cuneiform ; s, scapho-lunar ; os p, os prominens; 
epa, tendon of extensor patagii longus. 
The accompanying cut, drawn from a fresh specimen of B. 
virginianus , explains the form and position of the os prominens. 
It will be noticed that it is situated on the anterior surface of 
the distal end of the radius, and runs almost parallel with that 
bone, instead of standing erect as in the Falconidce . The radial 
portion of the tensor patagii longus terminates in the os promi- 
# nens, and is not continued to the first metacarpal. 
Apart from the Owls above noted, this bone has been found in 
Otogyps calvus , Heterospizias meridionalis , Buteo melano- 
leucus , B. pennsylvanicus , B. lineatus , Circus gouldi , Astu- 
ri?za pucker ani, and Haliceetus albicilla. 
A. - Os prominens of Otogyps calvus , full size. 
B. “ “ “ Bubo virginianus , seen from above to show 
articulation with radius, full size. 
