1872.] : 465 [Cope. 
Length, opistertial-cs.4s sar ts seb reer saw ees aontingels dott -016 
Width Nee or ee ee 026 
iON Mmanoinal ies ice leds tow nie lovers O11 
Width Eras iate OME SAL NP clay Sean. eee 016 
The three specimensare from the bluffs of Cottonwood Creek, Wyoming. 
NAOCEPHALUS PORRECTUS. Cope. 
Gen. et. sp. nov: Lacertiliarum. 
Established on an incomplete cranium, with vertebrae found associated. 
No teeth are preserved, nor any part of the mandible. The remaining 
portions of the cranium are, however, highly characteristic. 
The occipital descends posteriorly, and bears a pair of lateral ridges, 
which converge rapidly posteriorly. This bone is united with the pari- 
etal by suture, which is transverse ; its outline is rectangular, so as 
almost to reach the frontals, which are prolonged backwards on each 
side the parietal, leaving but a narrow exposure of the posterior processes “ 
the parietal. These extend backward, and are broken off in the spec 
men, but they probably formed parts of arches. The parietal is single, 
and there is no parietal fontanelle. The bone is triangular in outline 
with the apex anterior, dividing the frontals. These are contracted at 
the orbits, and have a projecting superciliary head ; anteriorly they are 
thickened. The postfrontals are of remarkable form. They are mas- 
sive, and compressed from before backwards; they rise considerably 
above the level of the front, and bear on their summits a cotyloid cavity, 
which is transverse to the axis of the cranium ; the use of this projection 
is obscure. There isan exoccipital foramen, and a large one in the poste- 
rior part of the frontal opposite the postfrontal elevation. 
The sphenoid is a compressed keel-shaped bone, rounded below, and 
with broad alee along much of its length. The occipital condyle is sub- 
cordate depressed in outline, with a vertical obtuse angle in the middle 
and the sides somewhat plane. 
A dorsal vertebra preserved has a single vertical capitular process, and 
a short hypapophysis. The neural canal is large, and the neurapophyses 
are attached by sutures. The cup is nearly round, very slightly trans- 
verse, and in vertical plane. 
The cranium is smooth above, except the anterior part of the frontals, 
which are finely rugose. 
This genus is more or less allied to the Thecoglossa, but better material 
will be requisite to decide the question of affinities fully. 
Found with the preceding specimens. 
M. 
Waidth cranium postirontals ss. 0. . ei ea is .072 
cto pariotalsOOMIGy . senre cel rs ts c ress eee eon .012 
De poh  posumroutal eds ce ver Cee een Oe Melee eee 018 
ct  prosphenold amuCnlOny vr ecers ree... UPDOCE OAS 014 
Diameter dorsal vertebra (Cup)... 6.66. ee .007 
This genus differs from Glyptosaurus, Marsh, in the total lack of era- 
nial shields, and from Saniva, Leidy, in the nearly round vertebral centra. 
A. P, 8§—VOL. XII.—36@ 
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