of the structure of whose skull are known, and this only recently,
from the Rev. W. Fox's unique specimen, first exhibited at the Meeting
of the British Association 1868, and described by Prof. Huxley
in the 26th vol. of our Journal. Of the skulls of Iguanodon Mantelli
and Megalosaurus Bucklandi, the only parts which have been
determined are incomplete mandibles and fragments of maxillae.
The skull of Hyloeosaurus is still, so far as I can learn, represented
by the single small fragment of the base imbedded, at the end of the
vertebral column, in the Tilgate-Forest slab, purchased by the British
Museum of the late Dr. Mantell, and figured by him in his ' Fossils
of the British Museum,' and by Prof. Owen in the ' British Fossil
Reptilia ; ' and the skulls of Polacanthus Foxii, Pelorosaurus, the
Cetiosauri, and Streptospondyli are altogether unknown.
In August 1865 I saw in the Rev. W. Fox's collection a fossil which he had recently found in Brixton Bay. It was plainly a splendid fragment of what before its mutilation had been a very large skull. A strong impression of its reptilian nature, together with its marked dissimilarity to the skulls of the other orders of this class found in the same formation (Chelonia, Crocodilia, and Pterosauria), led me to assign Mr. Fox's skull to a Dinosaur; and its size pointed to one of the largest, as Iguanodon Mantelli.
In September 1869 I myself obtained at Brooke (a locality not far from where Mr. Fox discovered his skull, and one famous for the large number of Dinosaurian remains it has furnished) the hinder part of a skull, which repeated the principal features of that which I had seen in 1865 in Mr. Fox's collection, and which also supplied several parts wanting in his, particularly the occipital condyle, proving my impression of the reptilian nature of his skull to have been well founded.
Knowing Prof. Huxley to have been recently engaged on the osteology of the Dinosauria, I showed him my prize soon after my return to London ; and he confirmed my opinion of its probably Dinosaurian nature. A paper upon it from him would have been so valuable that it would have given me the greatest pleasure to have left its description in his hands ; but his many and increasing engagements have not allowed this ; and, unwilling to withhold any longer from fellow- workers what, I believe, is a distinct addition to the craniology of this interesting order, I now venture myself to bring the skull under your notice. In doing this I am happy to acknowledge my obligations to Prof. Huxley for assistance as valuable as it has been kindly rendered.
The specimen consists of the nearly perfect cranium proper, the facial segment having been broken off across the orbits. The freedom of its outer surface from matrix, its polish, the smoothness of the once rough fractured edges, and the presence of many recent Serpuloe upon it show that it had been during a long time lying exposed in the sea before it was thrown upon the shore.
Seen from above (Pl. XI. fig. 3), its outlines are roughly like those of an hourglass, owing to the strong incurve of the temporal regions. The deep temporal fossae are bounded in front by massive postorbital
