RECORDS OF IV. A. MUSEUM. 
[245 
Description of the Remains. 
The atlas vertebra is perfect, its inferior arch completely 
ossified and the transverse processes fused to the rest of the 
vertebra. I ts neural arch is well developed antero-posteiioily, it 
has a steeply inclined anterior surface and a gradually sloping 
posterior one. The neural spine is represented by an anteriorly 
directed tubercle from the base of which a rounded ridge extends 
to the anterior border of the transverse processes. Ihe greatest 
width of the anterior surface of the arch is but 6.5 mm. compared 
with 10.5 in E. (P.) robust a. The extent of the posterior surface, 
measured from the tip of the neural spine to the posterior margin 
is 15 mm., the arch is not as flat as in Dun’s specimen and is much 
more slender, although it helps to form a larger concavity for the 
reception of the odontoid process of the axis. The inferior atch is 
slender and agrees with Dun’s figures, 1 but the curve is not quite so 
regular, resembling Tachyglossus in this respect. Both the anterior 
zygapophyses are large, irregular in outline, with an anterior lobe, 
their lower end passes imperceptibly into the inferior arch. They 
are concave vertically and almost flat horizontally. The posterior 
zygapophyses are ear shaped and possess well-marked posterior 
lobes ; downwards they merge gradually into the inferior arch, 
their apex projects from the lateral mass to a marked degree ; they 
are but slightly concave vertically and horizontally. Ihe trans- 
verse processes are complete, they extend outward and backward 
with a slight downward curve and a well marked ridge on their 
external border; there is a slight concavity in the anterior region of 
their upper surface, but the main mass of each process is convex 
above and below. 
The area bounded by the neural and inferior arches is deeper 
and broader than in E. (P.) robusta. The extreme width of the 
vertebra, including the transverse processes is 59 mm. and the 
heighth to the tip of the neural tubercle 33 mm. 
The united clavicles and episternum form a bow-shaped mass 
whose constituents are completely fused, rendering it impossible to 
distinguish the individual clavicles and the upper part of the 
T-shaped episternum. It is roughly trihedral in section, the well 
marked antero-superior ridge gradually passing downwards to the 
1 Loc. cil. pL XI, figs. 5 and 6. 
