LOPHIODON, OR PALA®OTHERIUM. 309 
Middle phalanx of right fore-foot, nat. size. Eocene Marl, Isle of Wight. 
LOPHIODON, or PALAXOTHERIUM. 
Tur fossil bone above figured is a median phalanx of 
the right fore-foot, and was submitted to me as the bone 
of an Iguanodon. There is, in fact, a considerable general 
resemblance between the middle phalanges of this great 
herbivorous reptile and those of the larger hoofed Mam- 
mals; but with respect to the fossil in question, the con- 
figuration of the lateral surfaces for the attachment of the 
ligaments; the production of the inferior border of the 
distal articulation into a process () for the insertion of 
the flexor tendon; and the greater curvature or portion 
of a circle described by the distal articular extremity, (¢, e,) 
which indicates a greater extent and freedom of flexion 
and extension of the toe than the cold-blooded reptiles 
possess; all combine to prove the fossil to have belonged 
to the more active, warmer-blooded and higher organized 
Pachyderm. It agrees most closely with the characters 
of the corresponding phalanges in the large Tapiroid qua- 
