O. C. Marsh—Skull of Pteranodon. 425 
The premaxillaries are very large, and have coalesced with 
the maxillaries. They appear to extend backward to the large 
antorbital vacuities. These apertures apparently include both 
the anterior nares, and the lachrymo-nasal fossee, which are 
separate in most recent birds. 
he orbit is of moderate size, and oval in outline, the apex 
being below. There was apparently no ring of bony sclerotic 
aon since in the best preserved specimens no traces of this 
ave been found. : 
The quadrate is firmly codssified with the other cranial 
bones, and projects strongly forward. Its distal end is one of 
the most characteristic parts of the skeleton. 
The sagittal crest is of enormous size, and serves to balance 
the elongated jaws. It is very thin transversely, and during 
ite was probably more or less exible. In form and direction, 
it resembles the corresponding crest in the recent genus 
Basilicus. 
_ The occipital condyle is very small, and nearly hemispher- 
‘cal in form. It is directed backward, and but slightly down- 
ward, thus differing from this part in most of the members of 
he group. 
THe LowER J AWS. 
The lower jaws are very long, and quite sharp in front, 
corresponding closely in this respect with the end of the 
upper jaws. The rami 
Length, from extremity of sagittal crest to end of pre- 
maxillary, about 30 inches, or ---- -------------- 
Tranverse diameter of occipital condyle, ---- ---- --- ---- 8 
Distance from occipital condyle to distal end of quadrate, 105° 
Length of lower jaw, about, 23 inches, or-.------------ an 
Greatest’ depth, 2.0 oa eae ee sane et oot - 
Depth at articulation for quadrate,--.----.------------ 
