BY C. W. DE VIS, M.A. 29 
the Hydrosaurus or Odatria scapula exhibited by the present 
subject might have continued to be supposed within the 
limits of individual variation, notwithstanding immense superio- 
rity in size. The fossil consists of the articular portion of the 
scapula proper and that of the coracoid. The scapula neck is 
broad, and on its outer surface rather concave, resembling in 
the former respect that of Hydrosaurus; in the latter, neither 
of the living forms. The hinder wall of the glenoid cavity 
(Pl. IIL, gl.) has a downward extension which furnishes a pro- 
portionately larger surface of articulation with the head of the 
humerus. The small foramen at the base of the epicoracoid 
fenestra (PI. IIL. ef.) is round: in all other respects it has a 
close resemblance to the scapula of Hydrosaurus. The long 
diameter of the glenoid cavity is 4:5 c.m., its short diameter 
3°8 c.m., the corresponding measurements in Hydrosaurus being 
12cm.and10cm. From the middle of the anterior lip of the 
glenoid cavity to the margin of the round foramen the distance 
in the fossil is 4°0, in the recent bone 1'1 c.m. 
Assuming the length of the humerus to be a measure of the 
length of the entire animal the ratio between the two in Monitor 
would, if applied to the fossil, give a length of not quite ]2ft- 
for the extinct reptile—compared with Hydrosaurus that 1 ngth 
would be increased to 14ft. 6in, while in comparison with 
Odatria it would attain 15ft. 6in. If, however, we take the 
breadth of the bone at the distral end as the basis of comparison, 
we attain in the same series of comparisons 18ft. 2in., 20ft. 95in., 
and 25ft. 4in. Taking the mean of the results of the compari- 
son with Monitor, with which its affinities seem to be strongest, 
we arrive at a probable length of 15ft. for the owner of this 
humerus accompanied, however, by a massiveness of body and 
limb not preserved in its modern representatives. 
From thé scapula alone, which from wide difference of locality 
could not have belonged to the same individual as the humerus, 
we should be compelled to estimate the entire length of 
