0. C. Marsh—Siructure of Mosasauroid Reptiles. 459 
line near the middle there is a.sharp crest. The supra-occipital 
keel projects obliquely backward, and its posterior pe is sharp. 
The batiohenotd has the anterior lateral processes petbcs 5 
and strongly decurved, thus showing a marked difference from 
the last described species. There are eleven maxillary an 
twelve mandibular teeth, which have unequal facets externally, 
and irregular striz on the inner face. The palatines are alate, 
sigmoid in fore-and-aft outline, with the pointed anterior ends 
converging. ‘There are ten palatine teeth, all more or less pleu- 
rodont, the anterior four being entirely so. The quadrate has 
an elongated depression on the back of the ala near the middle ; 
and a deep semi-circular excavation under the hook, and behind 
the meatus. There is also a prominent smooth knob on the 
inner face, between the meatus and the large rugose knob at the 
end of the hook. The distal articular face has its anterior 
Measurements. 
Width of frontals between posterior angles,.-------- ---- bE omg 
Width in front of orbits, é ete ae 85° 
Depth of maxillary at anterior nareal expanse, .-.------- 33° 
nsverse diameter of basi-occipital on condyle, - ------- 44° 
reenter rs ce ee 26° 
eeneen of quadrata 2 ee 17 
Length of posterior hoo SO ES oa eee 52 
Transverse diameter of distal articular face,....-------+ 40° 
TO-p ior ; me pieces bine sel i ieeeee ‘“ 20° 
Length of axis with odontoid process, .-.-------------- 68° 
This species may be distinguished from Liodon curtirostris 
Cope, and Holeodue coryphceus Co e, by the number of teeth in 
the jaws, or in the alatines, as well as by other charac 
si ie above, shot 
ated species. The known remains now represen 
found last summer, in the upper Cocsaoosek salt by Mr. 0. 
Harger, of the Yale party, Mr. om S. Lane, guide, and the writer, 
Kane our explorations, near the Smoky Hill River, in Western 
