THE IGUANODON AND HYL.EOSAURUS. 
305 
The principal points in the above specimens are indicated by the follow- 
ing letters. 
a. The head. 
h. Inner tuberosity. 
c. Outer tuberosity. 
d. Deltoid crest, or ridge for the insertion of the deltoid muscle. 
e. Inner condyle. 
f. Outer condyle. 
g. Olecranal furrow or depression. 
PLATE XXXII. 
ertehrce and Dermal Bones of the Hylceosaurus. 
Fig. 22. Posterior portion of the spinal column of the Hylaeosaurus, from the Weald 
of Sussex ; one-sixth natural size. 
The series of nine verteorce anterior to the three terminal ones in this 
specimen, lies imbedded on the stone in a position the reverse of that 
of the other portions of the spinal column ; the haemal aspect of the 
bodies of the vertebrae, with the corresponding chevron bones (/, i, i), 
being uppermost. 
22“. Outline of the form and arrangement of the chevron bones in the distal 
part of the column. 
22*, 22"", 22*^. Illustrate the modifications of form in the chevron bones in 
the anterior part of the specimen. 
22^ Distal chevron bone. 
22^. Middle . 
22^. Anterior . 
Fig. 23. Dermal bone from the middle portion of fig. 22 ; one-half natural size. 
Fig. 24. Dermal tubercle or horn of the Iguanodon ; natural size ; from Ridgway, 
near Weymouth. 
