21 
restoration was made over the impression on the hard rock which enclosed 
the specimen, so there is no doubt as to its accuracy. This high, thin crest 
is thickened at intervals to give strength, but between these the united bones 
are very thin. 
The nasal is a trifurcate bone. A short antero-inferior branch rests 
on the frontal, unites with the posterior tip of lower limb of the premaxilla, 
and is flanked by the up-turned prefrontal. This portion undoubtedly sur- 
rounds the downward course of the narial passage. The supero-anterior 
branch extends far forward as a moderately broad but thin plate of bone 
and covers the narial passage and air chamber. The posterior branch is a 
moderate-sized spike which tapers to a blunt point and extends backward 
to overhang the occiput slightly and flank the thin upper limb of the pre- 
maxilla. 
The narial passage has not been worked out in detail in this species, 
but from a study of the contour of the bones and the analogy of other 
species, it appears to follow a course in the forwardly turned lower limb of 
the premaxilla to where it comes in contact with the upper limb of this 
bone, then being sharply deflected backward. From this point it continues 
backward in a horizontal plane, and is covered by the supero-anterior 
branch of the nasal. At the bifurcation of the anterior branches of the 
nasal the passage is again sharply deflected and continues forward and 
downward to the internal naris. Thus there are two U-shaped bends in 
the narial passage. Specimen No. 8631 shows that a somewhat similar 
course is followed in L. clavinitialis, though the fore and aft length is not 
nearly so great or not so nearly horizontal and thus the deflections are not 
so sharp. 
The prefrontal forms the anterior half of the superior portion of the 
orbit and is strongly developed and upturned to flank the posterior portion 
of the lower limb of the premaxilla and antero-inferior branch of the 
nasal. 
The lachrymal is similar to that of L. clavinitialis and the long, slender 
tongue of bone that extends upwards to meet the prefrontal just barely cuts 
off the premaxilla from the orbital rim. 
The jugal does not differ greatly from that of L. clavinitialis , but the 
postorbital bar extends up to meet an anterior process from the squamosal. 
The maxilla is moderatly massive and convex in front of the jugal 
overlap as in other species of the genus. It is not possible to give a detailed 
description of the teeth or the number or rows. 
The skeleton has not yet been prepared except the right ilium, but it 
is known that the forearm is much longer than the humerus. Field measure- 
ments give the length of the femur as 1,090 mm. which is 70 mm. longer 
than that bone in L. clavinitialis , though the skull of the latter species is 
only slightly shorter. 
The ilium is of much more slender construction and more down-curved 
than that of L. clavinitialis and both the anterior and posterior blades are 
thin. When compared with the former species, the great difference in the 
ilium and helmet-like crest suggests a distinct genus, but it is thought best 
to regard this new form as belonging to Lambeosaurus because of the 
analogy of the premaxillae nasals and narial passages. 
