426 O68. Marsh—Skull of Pteranodon. 
The skull of Pteranodon ingens, described by the writer 
‘from the same geological horizon, is about four feet in length. 
The skull of Pteranodon differs especially from that of the 
other known Pterosauria, in the following particulars: (1) the 
absence of teeth; (2) the absence of anterior nasal apertures 
distinct from the antorbital openings; (8) the presence of the 
elongated occipital crest ; (4) the whole jaws were apparently 
covered with a horny sheath, as in recent birds. 
Yale College, New Haven, April 24th, 1884. 
EXPLANATION OF PLATE XV. 
Figure 1.—Skull and lower jaw of Pteranodon longiceps, Marsh; side view. ‘ 
Figure 2.—The same skull ; top view. 
Figure 3.—The same skull; bottom view. | 
Figure 4.—Lower jaw of Pteranodon longiceps ; top view. 
a, Antorbital aperture; }, orbit; c, sagittal crest; d, angle of jaw; ¢ lower 
margin of upper jaw ; e’, upper margin of lower jaw ; / articulation of lower jaw; 
oc, occipital condyle ; q, quadrate bone; s, symphysis of lower jaw. 
All the figures are one-sixth natural size. 
