388 
DR. MANTELL ON THE PELOROSAURUS. 
The dimensions of this bone are as follow : — 
Length 54 inches. 
Circumference of the distal end 32 inches. 
Transverse diameter of the same 13 inches. 
Circumference of the shaft at the transverse section 17 inches. 
the fractured end of the deltoid ridge 23 inches. 
a. The head or proximal extremity. 
b. Distal or radio-ulnar articulation. 
c. Deltoid ridge. 
d. Inner condyle. 
e. Outer condyle. 
f. Transverse fracture exposing the section seen in fig. L. 
Fig. 2. Outline of the right humerus of a Gavial 18 feet long. 
2“. Anterior view. 
2*. Posterior view. 
Fig. 3. Humerus of the Hyleeosaurus. 
Fig. 4. Humerus of the Iguanodon ; from Philosophical Transactions, Part II. 1849, 
Plate XXXI. fig, 19^. 
PLATE XXII. 
All the specimens here delineated are in the British Museum : the figures are reduced y linear the na- 
tural size. 
Anterior caudal vertebrae and chevron bone of the Pelorosaurus': 
Fig. 5. The largest and most anterior bone of the series. 
5“, Perspective view showing the slightly concave anterior face of the body 
of the vertebra (a), the excavated form of the sides, the anterior oblique 
processes {g,g,) and the spinous process (e), with the pits or depressions 
for the reception of the heads of the oblique processes of the contiguous 
posterior vertebra (A). 
5®. Front view of the same fossil. 
5^ Posterior view, to show the remarkable character occasioned by the absence 
of oblique processes. The several parts in this and the vertebrae figured 
in the subsequent plates are thus indicated : — 
a. Anterior articulating surface of the body or centrum. 
b. Posterior face, 
c. Inferior or visceral aspect of the body, 
d. Neural arch, or neurapophysis. 
* 'ITiere is a typographical error both in the text and lithograph of this bone in the Philosophical Transac- 
tions, loc. cit., as to the scale of the figure ; it is marked reduced to it should be y linear the natural size. 
