authority of a verbal communication from Mr. Fox) renders it less
probable that the skull belonged to this Dinosaur than to an Iguanodon. In the ornithocephalic skull of Struthiosaurus, Bunzel, the
sutures also disappear ; but its broad rounded occiput, its large
downward slanting paroccipital processes (shown in the figures accompanying Dr. Bunzel's description), and the absence of the basisphenoidal swellings so conspicuous in my Wealden skull completely
distinguish it from this.
EXPLANATION OF PLATE XI.
Supposed skull of Iguanodon, from Brooke, Isle of Wight. Fig. 1. View of right side of the skull. Fig. 2. View of interior of the same. Fig. 3. View of upper surface of the skull. Fig. 4. View of posterior surface.
Fig. 5. View of under surface : pa, parietal crest ; t, temporal fossa ; sp, suspensorial process ; ot, occipital tuberosity ; bs, basisphenoid ; bps, basipresphenoid ; os, orbitosphenoid ; hpf, hypophysial fossa ; f, foramen magnum ; c, posterior opening of carotid canal ; c', anterior opening of same ; ii, v, vii, viii, ix, foramina of the respective pairs of nerves.
Discussion.
Prof. Huxley congratulated the Society on the progress being made in our knowledge of this interesting group of Reptiles and of their ornithic affinities.
Mr. Seeley remarked on the similarity of the internal cavity of the skull to that of Ichthyosaurus. Some of the external characteristics differed much from what he was acquainted with in other Dinosaurian skulls, which, in the base of the skull, more closely resembled those of ordinary lizards. He considered that the affinities of Dinosaurs hitherto demonstrated were in the direction of Teleosaurus, from which the position of what were supposed to be the optic lobes in this skull materially differed in being more reptilian. On the whole, from its want of similarity to Hypsilophodon, he was not prepared to accept this skull as that of an Iguanodon, and thought that some doubt attached to its affiliation with the Dinosaurs.
Mr. Hulke briefly replied, and observed that he had limited his speculations to those which legitimately arose from the facts before him.
