330 
DR. R. W. SHUEELDt’s MORPHOLOGICAL 
are to be found the two usual tuberosities for articulation with 
the bones of the antibrachium. 
In neither of the Trogon skeletons at hand do I find any 
sesamoid bones present at the elbow-joint ; but it is just possible 
that these birds may possess them, and that in the present 
instance they have been lost in the preparation of the skeleton ; 
I am inclined to believe, however, from the general appearance 
of the dried ligaments and other structures that have been 
retained in one specimen, that the Trogons do not have these 
ossicles at the elbow-joint. 
Turning to the bones of the forearm, we observe that the shaft 
of the radius is very slender and nearly straight. Its extre- 
mities are comparatively but slightly expanded, and on the 
whole this bone is not so powerfully developed as we find it in 
many birds of the same size. The interosseous space between it 
and the ulna is ample, but is largely due to the curvature in the 
shaft of the latter bone. The ulna has the usual form as we 
find it in some of the Passeres. Its olecranon process, however, 
is not conspicuous, while the shaft is smooth, subcylindrical, and 
devoid of the row of papillse for the insertion of the quill-butts 
of the secondaries of the wing, so prominent in some birds, as, 
for instance, many of the Picidce. 
Hadial and ulnar ossicles compose the carpal joint, and make 
the usual articulations with the surrounding bones. I am unable 
to discover any sesamoids about this joint, and am of opinion 
that none exist. 
Extending our observations to the hand, we may note the 
peculiar form of its main bone, the carpo-metacarpal. This 
peculiarity does not consist in. any radical change of its form as 
it is found to be in most birds, but of the unusual width it as- 
sumes at its distal end, in the antero-posterior direction (PI. XIX. 
fig. 13). The increase of surface thus gained is for the accom- 
modation of the articular facet for the single and termiual 
phalanx of mid-metacarpal digit, here disproportionately large 
as compared with the bones of the other two phalanges. 
Pollex phalanx is small, slender, and trihedral in form ; it is 
not provided with a claw at its distal extremity. 
A very similar joint is the distal phalanx of index digit, and 
this, too, is without a terminal claw. 
The proximal bone of this finger has the general form it as- 
sumes among birds, but in the present instance the expanded 
