644 S. W. WILLISTON 
two together below gently convex from side to side. The lateral 
outlines of the mandibles from below have a gentle concavity near the 
middle, curving rather strongly inward behind. The inferior margin 
of the jaw turns upward behind rather abruptly, and is narrowed 
from side to side. The sutures of the mandible are not certainly 
distinguishable. Posteriorly the articular projects but very little 
beyond the quadrate. 
Vertebrae (Figs 4 ff.).—The remains of twenty-three vertebrae are 
preserved in an uninterrupted series connected with the occipital 
condyles. Of these the sixteenth, seventeenth, eighteenth, and 
nineteenth are represented by their arches only, their centra lost from 
the block of matrix wholly or for the most part. As far as the fifteenth 
the hypocentra lie closely associated, save for a twist at the seventh, 
in a somewhat sigmoid curve, with the spines vertical or nearly sb. 
At the sixteenth the column was twisted so that the spines lie hori- 
zontally to the right, the left leg with its parts but little disturbed lying 
for the most part upon or at the right side of the column with its 
ventral side uppermost. The femur is much flexed upon the leg 
and its head turned across and above the posterior vertebrae. At the 
end of the twenty-third, or rather in the twenty-fourth, another 
break occurs in the series as preserved in the matrix. The succeeding 
block of matrix includes four vertebrae, and was much worn. Erosion 
of the projecting ends of the series in the two blocks prevent their 
positive union. The first eroded vertebra of this series bears the 
left sacral rib, and, lying above it, the proximal part of the left illum. 
By joining the two eroded ends of the series with the acetabulum 
lying uppermost, the head of the femur nearly fits into it. It is certain 
that the leg suffered no disturbance whatever after the decay of the 
flesh covering it, save a slight rotation of the tibia outward and the 
displacement of the fibula. It clearly occupies its proper position as 
regards the vertebral column, from which it follows there could not 
have been more than one or two vertebrae lost. 
The axis is much broader from side to side than the following 
vertebrae, and is very short antero-posteriorly. Its large articular 
surfaces fit closely the condyles of the skull. Its posterior margin 
below is nearly parallel with the anterior. JI can discover no indica- 
tions of separated pleurocentra, though such may have existed. Its 
