406 PEOF. H. G. SEELEY ON TSEPHOPHOEUS POLYGONTJS. 



30. [Rote on Pbephophoetjs polygonus, v. Meyer, a .new Type of 

 Chelonian Eeptile allied to the Leatheey Tuetle. By Pro- 

 fessor H. G. Seeley, F.E.S., P.G.S., &c, (Head May 12, 



1880.) 



(Plate XV.) 



"When I was in Vienna in tlie spring of 1879, Pranz Eitter von Hauer, 

 the Director of the Imperial Geological Survey, requested mo to 

 examine and describe the remarkable organism on which Yon Meyer 

 had founded the genus Psephophorus, which, although noticed by 

 himself, by Von Meyer, and, more recently, by Dr. Puchs, has never 

 been figured. Its nature was at first sight so problematical that 

 opinion leaned to the conclusion that it was the dermal covering 

 of an Edentate closely allied to the Armadilloes. The dorsal sur- 

 face of the fossil was perhaps insufficient to settle this question 

 without a good deal of comparative work ; but Yon Hauer cour- 

 teously allowed me to partially develop some fragments of bones, 

 which are imperfectly preserved on the underside of the intractable 

 sandstone matrix of the slab ; and these fragments of procoelous 

 vertebrse proved to be altogether reptilian ; and though differing from 

 the vertebrae of known reptiles, yet, by the forward projection of the 

 zygapophyses, they indicate the animal to be Chelonian, and there- 

 fore show the fossil to be more nearly allied to Sphargis than to any 

 other type in the Chelonian order. 



When Yon Meyer first gave a name to this genus (' Jahrbuch,' 

 1846, p. 472), it was only known to him by isolated dermal plates ; 

 but subsequently a drawing was sent to him by Partsch, and on 

 that he made a further note in the ' Jahrbuch ' for 1847 (p. 579). 

 This specimen, then in Pressburg, he describes as a fragment of a 

 carapace, containing seventy bones touching each other, and show- 

 ing the impressions of many others. Among these dermal bones 

 rises a middle row, in which the plates are longer and more evenly 

 pressed together in front and behind, while the other plates are 

 placed together irregularly. He adds his conviction that it may be 

 referred to the Dasypodia. It remained without further notice till 

 1868, when Yon Hauer, in the * Yerhandlungen der k.-k. geolo- 

 gischen Eeichsanstalt ' (p. 387), mentioned briefly that the fossil 

 had been acquired for the Museum of the Imperial Geological Survey 

 in Vienna. He also, in 1 870, in the same publication (p. 342), 

 makes a note on Psephophorus, mentioning that the museum had 

 acquired not only the original type specimen, but a second larger 

 slab, fitting the first, and containing a larger portion of the same 

 carapace; for while the first piece contained six median plates, 

 characterized by a raised keel, extending in a straight line, and 

 sixty-four smooth lateral plates in a connected position, on the second 

 slab of sandstone are five more median plates and nearly a hundred 

 more lateral plates. These form together an even arched shield, 



