CAMBRIDGE UPPER GREENSAND. 
61 
Case. Shelf. 
X b 
b 
b 
No. 
12 An atlas and axis badly preserved, but with 
the posterior cup very deep, as in b . 4. 
13 This is an alias to which the axis was only 
ancliylosed at its inferior border. It is 
the only specimen showing such a separa¬ 
tion. It is remarkable for the great length, 
of the flat inferior sides, which meet at an 
angle much less than a right angle. High 
on the right side may be seen the elon¬ 
gated tubercle for the rib. The species 
appears to be distinct from all others. 
14 A small atlas and axis, very short from front 
to back, and at both ends heart-shaped, 
with the very long inferior sides convex. 
X c 1—14 Sclerotic bones defending the eye. They ap¬ 
pear to have been slightly connected and 
are usually separated. Each bone is thin 
in front and thickens behind, the outer 
and back part being convex, the inside 
flat or concave; they are joined by an 
irregular sutural union or obliquely over¬ 
lap. c .12 is an example of three bones 
remaining united, and illustrates their 
irregular consecutive form and size. The 
bones are unusually thick, Lias speci¬ 
mens rarely attaining half their thickness. 
About 20 would complete the orbital cir¬ 
cle. c . 14 is unusually thin. 
c 15—22 Examples of the quadrate bone. (Tympanic 
of Owen.) This is a bone of a quadrat o- 
reniform outline, thickening distally to 
form the elongated crescentic longitudi¬ 
nally grooved condyle for the lower jaw. 
The specimens vary in form, and may be 
compared with the Clielonian quadrate 
bone. 
c. 15 and c . 16 are right and left quad- 
