Oeological Society. 137 



compressed laterally, the neural arch comparatively depressed and 

 thrown out laterally above by the inferior V-shaped approximation 

 of the side of the centrum. Several other peculiarities were also 

 pointed out. 



The paper concluded with notes on other vertebrae of similar cha- 

 racter from Tilgate and Brook, and attention was called to a Croco- 

 dilian cervical vertebra with the procoelian cup from the Purbeck 

 beds. 



.5. " On a Sacrum, apparently indicating a new type of Bird 

 (Ornithodesmus cluniculus, Seeley), from theWealden of Brook." By 

 Prof. H. G. Seeley, F.R.S., F.G.S. 



After some remarks on the characters of the sacrum in Birds, 

 Ornithosauria, and Dinosauria, the author proceeded to describe a 

 sacrum composed of six vertebrae in the Fox collection, now at the 

 British Museum, and then to compare the fossil with the correspond- 

 ing bones of the three groups named. The resemblance to the 

 Dinosaurian and Ornithosaurian sacral vertebrae was less than those 

 which connected the fossil with birds. From the latter it was dis- 

 tinguished by the smaller number of vertebrae in the sacrum, the 

 absence of sacral recesses for the lobes of the kidneys, and the form 

 of the articular face of the first sacral vertebra. But the small 

 number of sacral vertebrae in Archceopteryx, the want of renal re- 

 cesses in IcJithyoniis, and the characters of the articulation in the 

 Solan Goose showed that these differences were not essential ; and 

 the author concluded that the fossil belonged to a true bird, but that 

 it formed a link with lower forms, and approximated more to Dino- 

 saurs than did any other Avian type hitherto described. 



May 11, 1887.— Prof. J. W. Judd, F.R.S., 

 President, in the Chair. 



The following communications were read : — 



1. " Further Observations on Hyperoda'pedon Gordoni." By Prof. 

 T. H. Huxley, LL.D., F.R.S., F.G.S. 



The Author briefly noticed the circumstances under which he 

 first described the occurrence of Lacertilian and Crocodilian fossils 

 in the Elgin Sandstones, and the confirmation which his views as to 

 the Mesozoic age of these remains had received from the discovery 

 of Hyperodapedon in English Triassic rocks and in India. The 

 original type of Hypej-odapedon Gordoni from Elgin was, however, 

 in bad condition, and the receipt at the British Museum of a second 

 much better preserved skeleton, found in the Lossiemouth quarries of 

 the same neighbourhood, had enabled him to add considerably to the 

 known characters of the genus, and to compare it more thoroughly 

 both with the recent Sphenodon (or Hatteria) of New Zealand and 

 with the Triassic Bhynchosaurus articeps, several specimens of which 

 are in the British Museum palaeoutological collection. 



