Geological Society of London. 41 



Geological Society of London. — ^November 19, 1873. — Professor 

 Eamsay, P E.S., Vice-President, in the Chair. The following com- 

 munications were read : — 



1. " Supplemental Note on the Anatomy of ffypsilophodon Foxii." 

 By J. W. Hulke, Esq., F.E.S., F.G.S. 



The material for this note was a slab from Cowleaze Chine, con- 

 taining portions of two individuals of Hypsilophodon Foxii, one con- 

 sisting of a skull with a great part of the vertebral column, the 

 other of a portion of the vertebral column. The author described 

 some details of the structure of the skull, and especially the palatal 

 apparatus. The pterygoids, which are not mesially joined, have a 

 stout body, the posterior border of which bears a very large basi- 

 sphenoidal process, and the left pterygoid retains the root of a strong 

 quadratic process, in front of which the hollow outer border runs out 

 into an eetopterygoid. In front of the pterygoids the palatines are 

 partially visible, also separated by a fissure. Of the eight vertebrae, 

 the three last are firmly anchylosed, and the seventh and eighth 

 form part of the sacrum. They are constricted in the middle, 

 and their transverse processes, which spring from the junction of 

 two vertebrge, are bent backwards, joining the dilated outer end of 

 the transverse processes of the next vertebra, including a large sub- 

 circular loop. The second fragment of a vertebral column, which 

 belonged to a smaller individual, includes the sacrum and several 

 vertebra. Near the skull the slab contains several very thin bony 

 plates of irregularly polygonal form, regarded by the author as 

 dermal scutes. In connexion with the question of the generic rank 

 of Ifypsilopliodon, the author stated that in Hypsilophodon the 

 centra of the sacral vertebrge are cylindroid, and rounded below, 

 whilst in Iguanodon they are compressed laterally and angulated 

 below. 



Discussion. — Mr. Boyd Dawkins thought there was as much distinction between 

 HypsilopJiodon and Iguanodon as between Hipparion and Eqtms, and that this was 

 quite sufficient to be regarded as generic rather than specific. He was not satisfied 

 as to the additional bone in the foot in Mr. Beccles's specimen, but thought it 

 might belong to some other part of the animal. He did not accept the received 

 view as to the character of the upper teeth of Iguanodo7i. 



Mr. Seeley considered that the author was likely to substantiate his opinions. 

 He pointed out certain differences in the structure and form of the maxillary and 

 other bones of the skull in HypsilopJiodon and Iguanodon, and especially in the 

 maxillary. He attached great importance to the thickening of the enamel at the 

 base of the teeth of Hypstlophodon, which approximated to that which was found 

 in some mammals. The teeth commonly reputed to be those of Iguanodo7i 

 might, he thought, belong to different species, if not genera, and showed some 

 divergence in character. The obsei-vations on the palatal bones of HypsilopJiodon 

 were, he thought, calculated to throw great light on the anatomy of Dinosaurs. 



2. "The Drift-beds of the North-west of England.— Part 1. Shells 

 of the Lancashire and Cheshire Low-level Boulder Clay and Sands." 

 By T. Mellard Eeade, Esq., C.E., F.G.S. 



The author commenced by explaining a section in a cutting at 

 Bootle Lane Station in which most of the beds seen about Liverpool 



