322 SHUFELDT. [Vot. II. 
ber of cervical vertebra, and the number of true dorsals, in any 
particular species. In the case of the total count for the verte- 
bree in any adult bird of the kind alluded to, the trouble is with 
the pelvic sacrum, and the skeleton of the tail. In nearly 
every example it is almost impossible to decide with certainty 
as to the number of vertebrz that have been incorporated in 
its fusion; while in the case of the tail, the pygostyle is the 
stumbling-block, for sometimes in representatives of the same 
species this bone in one individual will thoroughly appropriate 
to itself a terminal caudal vertebra, that will perhaps remain 
free in the other, thus making an additional segment for a bird 
of the same species. Then, again, it is pretty well agreed that 
when we come to define the line between cervical and dorsal 
divisions of the column, we look chiefly to the ribs for assist- 
ance; yet these are by no means to be always relied upon; as 
sometimes, in the same species, an additional pair may remain 
free at the further end of the cervical region, or an additional 
pair (always at the anterior part of the dorsal division) may 
connect with the sternum by a pair of hamapophyses. So 
that one observer might state that the first pair of free ribs 
in a certain species of bird were to be found upon the 13th 
cervical vertebrze, while another observer, equally careful, finds 
an individual of the same species wherein it is the 14th cer- 
vical that has the leading pair of free ribs. Thus it is that 
confusion and doubt creeps into the work. 
After having paid no little attention to the osteology of birds 
for more than ten years, now, I am fairly convinced that there 
is but one safe or very nearly safe method of arriving at the 
total number of vertebrae in the spinal column of any particular 
species of the class, and to do it we should have the prepared 
skeletons of the young of the species, two, or, better, three, of 
them, made just at the time when fusion is about to take place 
among the vertebrz, which eventually go to form the pygostyle 
in the adult, and when the vertebre composing the pelvic 
sacrum are all still individualized. Then the count can be made 
with certainty, and we should not fail to have by us at the time 
several skeletons of the adult of the same species for compari- 
son. Finally, our remaining difficulty, it is evident, cannot be 
settled in any such manner, and the only course left to pursue 
here, is to state, if possible, the general rule and the noted 
