TOOTHED BIRDS. 233 
Sub-Class II—Tootuep Brrvs (Odontornithes). 
These strange fossil birds 
were discovered in the creta- 
ceous beds of this country by 
Professor Marsh. Their rep- 
tilian and fish-like characteris- 
tics are seen in the vertebra, 
which are biconcave. The jaws, 
long and slender, were armed 
with teeth (Fig. 274) placed in 
sockets as are those of the croc- 
odile. Some were fliers and oth- 
ers had rudimentary wings. The 
Hesperornis was a large aquatic 
bird about six feet in height. 
Its jaws were supplied with 
teeth set in grooves, the wings 
were useless and rudimentary, 
while the feet were like those 
Fic. 274.—Bird with teeth, showing jaw with teeth, the sockets, a tooth 
enlarged, and section of the backbone. (After Marsh.) 
