53 
The lachrymal, as shown on the left side of specimen, No. 8500, is 
especially attenuated, its length being more than three and one-half times 
the maximum breadth. It forms much of the median anterior rim of the 
orbit. The narrowed upper extremity apparently meets the prefrontal, 
and the slender distal extension is intercalated between the jugal and 
premaxillary, the extreme end passing downward between the premaxillary 
and maxillary. There is a moderate-sized lachrymal foramen. 
The jugal is deep and, except for a more angular development of its 
posterior inferior extension, does not present any other unusual features. 
In front it is strongly in contact with the maxillary and less so with the 
lachrymal. Its exact posterior contact with the quadratojugal is not shown 
in these specimens, but it probably met the quadrate above the quadrato- 
jugal as in all other hadrosaurs except Krilosaurus navajovius Brown. 
The quadratojugal, quadrate, and postorbital are almost exactly com- 
parable to those bones in other crested hadrosaurian skulls of equivalent size. 
The squamosals are irregularly shaped triradiate bones, whose wide, 
medially directed branches narrowly meet on the median line above the 
parietal much as in Lambeosaurus. In many of the duck-billed dinosaurs, 
however, the squamosals are separated on the midline by the interposition 
of the parietal. The only exceptions in this respect found outside of the 
Lambeosaurinse are in the genus Prosaurolophus of Brown 1 and in an un- 
described hadrosaur in the collection of the Survey from the Lance form- 
ation of southern Saskatchewan. The squamosals are very narrowly 
separated in Cheneosaurus. 
The parietals. as in other helmet-crested dinosaurs, lie below the level 
of the supratemporal arcades. A thin but comparatively high median 
longitudinal ridge developed on the coalesced parietals divides the supra- 
temporal fossae, but the posterior end of this crest does not appear to rise 
to the level of the squamosals as in a skull of Lambeosaurus now before me, 
but passes beneath, though apparently not reaching the occipital aspect. 
The sutures joining the elements forming the brain case have nearly all 
become coalesced, but so far as determinable they closely resemble a cranial 
fragment (No. 8502) of a skull of Lambeosaurus in the Survey collections, 
in which these sutures are clearly and beautifully shown. 
The median crest of the parietals subsides before reaching the anterior 
end of this bone where it widens out transversely to join the frontals at 
the centre and the postfrontals laterally, and as in Lambeosaurus effectually 
excludes the frontals from direct participation in the boundaries of the 
supratemporal fossae. It cannot be determined whether a tongue of bone 
is sent forward between the frontals as in Lambeosaurus , nor can the suture 
between the parietal and the underlying prootie be observed in this speci- 
men. 
The frontals are wider than long, and strongly swollen, indicating a 
brain of similar shape and proportions to that of Lambeosaurus instead of 
the compressed elongated brain found in Edmontosaurus and Thespesius. 
The obscure condition of the fronto-nasal region makes a study of its 
features particularly difficult, but the nasals seem to extend forward from 
their union with the frontals for some little distance before turning back- 
ward and upward to enter the crest proper. On either side they extend 
mull. Am. Mus. of Nat. Hist., vol. 35, 1916, Figure 3. 
