336 
DR. R. W. SHUFELDt’s MORPHOLOGICAL 
I place the just amount of weight that should attach to the 
number of these segments in the spinal column of any bird, I 
think it should be borne in mind that these vertebrae are as 
much entitled to he considered in the light of the special form 
each or any of them may assume, as is any other part of the 
skeleton. 
The day may yet come when the question of the exact affinity 
of avian forms (or any other class of vertebrates for that matter) 
will have arrived at such a point of refinement as to require 
that even the morphology of each vertebra shall be known, to 
assist us in correct decisions. In the table which I here 
introduce (p. 335) the number of ribs and some few other points 
which I deem it well to compare have been entered. 
So far as we are able to judge by a comparison of these, it 
would seem that, taking into consideration the kind of data pre- 
sented, Trogon comes nearer to Geococcyx in its vertebral column 
than it does to any of the Caprimulgi. But it must be remem- 
bered that it is really very difficult to discern any truly striking 
resemblances among the vertebral columns of the several birds 
under consideration. 
Turning to the pelves, we find on comparing the pelvis of 
Trogon with that bone as we find it in some of the Nightjars and 
Whip-poor-wills, that there is a certain superficial likeness which 
strikes us ; but when we descend to the comparison of details, we 
are again met by the fact that these resemblances are purely 
superficial. Of course neither the pelvis of Chordeiles nor 
Trogon reminds us in the least of the unique pelvis which so 
conspicuously characterizes the skeleton of Geococcyx. How 
they would compare with certain other Cuckoo-like birds I am 
unable at present to say, from lack of proper material on which 
to form an opinion. 
Passing to the sternum (and I have figured this bone for both 
Chordeiles and Geococcyx in my memoirs above referred to, 
and for Trogon in the present paper), we are at once struck by 
the resemblance between the sterna of Trogon and Geococcyx ; 
the bones here are really very much alike, and both are 
essentially different from the single-notched sternum of Chor- 
deiles. 
Coming next to the shoulder-girdles, we are once more at 
sea, for these parts not only have no special likeness to each 
other, so far as Trogon and the Caprimulgi are concerned, but 
