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104 Bulletin American Museum of Natural History
[Vol. LIX
anteriorly, and appears not to reach the orbit, being crowded out by the postfrontal
and jugal, a feature undoubtedly related to the forward position of that opening.
The frontals are long and narrow. The prefrontals are narrow, but extend forward
nearly to the nares lateral to the nasals, which elements have a posterior wedge-shaped
extension along the outer sides of the frontals. The premaxillae carry an anterior
prolongation of the supraorbital lateral line canals. The lacrymals were wedged in
between maxilla and prefrontals, and I cannot be certain whether they reach the nares.
Posteriorly they effect a contact with the elongate jugal below the orbits. The maxille
are very long, reaching back to about the anterior end of the quadrate-jugals. The
marginal teeth are rather thinly spaced.
Curiously enough, I have been unable to obtain a satisfactory view
of the palate in any one of the rather numerous specimens. Our knowledge
of it is gained mainly from specimens laterally crushed which exhibit
portions of the palate between the jaw margins. Such evidence
as we have tends to show that it was similar, in most respects, to that of
Erpetosaurus radiatus.
The details of the braincase are not known. The parasphenoid was
toothed for much of its extent. The pterygoids articulated movably
with the basisphenoid region; they extended far forward, to about the
level of the palatine, with interpterygoid vacuities probably of moderate
size. There is some evidence that the palatal ramus bore a series of large
teeth-a very unusual circumstance-as well as a series of smaller
" denticles. " Three large sets of palatal teeth are present, presumably on
the ectopterygoid, palatine and prevomer. Those on the ectopterygoid
Fig. 10.. Colosteus scutellatus. Type of "Diceratosaurus robustus," X Y.
are the smallest; the others, in several instances, show both teeth of a
pair functioning at the same time. The contacts between the palatine
and ectopterygoid, seen in one instance, seem to be comparable to those
in 'Erpetosaurus.
The lower jaw is present in several cases but only its outer surface is
seen in its entirety. The dentary extends back nearly to the posterior
end, in agreement with the posterior reach of the maxillary above. It
bears a series of rather stout but thinly spaced marginal teeth, and a