or Toothed Birds of North America. 269 
would be required to convince him that they were parts of one 
and the same bird. ‘The jaws and teeth present reptilian 
characters wholly unknown in modern birds, while the base 
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found alone with the jaws and teeth, would force any anato- 
os the conclusion that he had before him the remains of a 
reptile. 
_ “The skeleton of ichthyornis, as we know it to-day, can be 
interpreted only, in the light of modern science, by supposing 
that certain parts have become highly specialized in the direc- 
tion of recent birds, while others have been derived, with but lit- 
_ tlechange, from a reptilian, or even a more lowly, ancestry. In 
4 the Wings, the most characteristic modern feature is the codssi- 
teeth are evidently a strong reptilian feature, and, before the 
Many reptiles, and is seen in Hesperornis, but is unknown in 
all other birds. The form of the skull and the obliteration of 
_— the cranial sutures are points of resemblance to many: 
otal birds. 
* 
* * at * * 
mo 2 great abundance mingled with those of Jehthyornis. 
These fossils occur in the bed of the old Cretaceous ocean in 
