1869.] HUXLEY HYPEKODAPEDON. 141 



sandstones of Elgin and Eoss with the Old Eed Sandstones beneath 

 them, I willingly adopt the view established by snch fossil evidence, 

 and consider that these overlying sandstones and limestones are of 

 Upper Triassic age." 



Shortly after these new lights upon the structure and stratigraphi- 

 cal position of Hyperodapedon had appeared, the able Director of 

 the Geological Survey of India, Professor Oldham, who happened to 

 be in England, drew my attention to some specimens obtained from 

 Maledi, in Central India, and presented to this Society in 1860 

 by the Eev. Mr. Hislop. Among these were fragments of large jaws 

 with teeth, which presented aU. the characters of Hyperodarpedon ; 

 and during the past autumn I received from Dr. Oldham a consider- 

 able number of similar remains, associated with those of Labyrintho- 

 donts and Crocodilian reptiles. The peculiar interest of this discovery 

 arises not only from the sudden, enormous extension of the dis- 

 tributional area of Hyperodapedon, but still more from the circum- 

 stance that Dicynodonts have been found in the same Indian strata, 

 and, thus, that we get a step nearer to the determination of the age 

 of the remarkable reptiliferous formations of Southern Africa, the 

 Triassic or Permian age of which was already highly probable. 



The last fact which needs to be mentioned in this history of the 

 gradually growing importance of the genus Hyperodajpedon is the 

 highly interesting and important collateral evidence as to its age 

 obtained by Mr. Whitaker, who will presently give you an account 

 of the precise position in the Trias of Devonshire in which a speci- 

 men of the jaw of Hyperodajpedon, which he brought to me a few 

 weeks ago, was obtained. 



I now proceed to describe the most important remains of Hypero- 

 dapedon which have come into my hands ; and I shall speak first of 

 the specimen on which the genus was founded, which is the pro- 

 perty of the Elgin Museum, and was sent to me in 1858. 



The remains of this specimen are exhibited by the opposed faces 

 of broken blocks of sandstone, some of which have been separated 

 by splitting along the plane in which the fossil lay. On one of 

 these blocks are the indications of seventeen vertebrse in a continuous 

 series, though slightly disturbed from their normal position here and 

 there. The bodies of all these vertebrae have about the same length, 

 viz. 0-9 in. or 0-95 in. They are so much constricted in the middle 

 as to be almost hourglass-shaped, and their terminal articular sur- 

 faces are slightly concave. In most of the vertebrae the neural 

 arches and spines are shown indistinctly, or not at all ; but the sixth 

 in order from the anterior end of the series is tolerably complete, 

 and exhibits a broad and not very high spine, the summit of which 

 is somewhat narrower than the base. This passes into the arch of 

 the vertebra, which exhibits well- developed articular processes. 

 The total height of the vertebra, from the lower edge of the posterior 

 articular surface to the summit of the spine, is 1*85 in., that of the 

 posterior articular surface of the centrum being 0*7 in. 



The fourteenth vertebra of the series, from its general character 



