Ix PEOCEEDINGS OF THE GEOLOGICAL SOCIETY* 



The five new genera have been defined in a notice commnnicated 

 to the Eoyal Irish Academy by Dr. Wright^ on behalf of Professor 

 Huxley and himself, under the names of Uroconchjlus, OpJiiderjpetonj 

 Ichthyerpeton, Keraterpeton, and Lejpterjpeton. Ophiderpeton is re- 

 markable for its extremely elongated and snake-like form ; Icthyer- 

 p)eton for its fish-like body and short limbs ; while Urocondylus, Ke~ 

 raterpeton, and Lepteipeton have Salamander-like forms and well- 

 developed limbs. In all, the vertebrse are abundantly ossified, and 

 there are no traces of persistent branchial arches, so that they pre- 

 sent very important diff'erences from Arclioegosaurus. The authors 

 then show that four of these five genera present unmistakeable re- 

 mains of the ventral dermal armour characteristic of the Labyrin- 

 thodonts, and that from this and other circumstances there can 

 be little doubt that they all belong to that group of extinct Am- 

 phibia. 



Professor Huxley informs me that, up to the time when these di- 

 scoveries were made, eight genera, in all, of higher organization than 

 fishes were known to occur in rocks of Carboniferous age in Europe, 

 and five in America. Of the eight European genera, only Arclice- 

 gosauriis, PJiolidog aster, and Anthracosaurus were known by more 

 than mere fragments ; nor do we possess at this moment a know- 

 ledge of the nature of the limbs in any one of these genera, except 

 Archcegosaurus. The five American genera Baphetes, Raniceps, 

 Dendrerpeton, Hylerpeton, and Hylonomus were much more fully 

 known ; and it was a curious problem whether further research in 

 Europe would tend to reveal the existence during the Coal-period of 

 small Amphibia with well-ossified vertebrae and well-developed limbs, 

 like the American forms, or whether it would show that the Labyrin- 

 thodonts of the European area rather adhered to the Archoegosaurian 

 type already known to occur in Europe, but not hitherto found in 

 America. 



So far as the Irish discoveries have yet gone they prove the existr- 

 ence, during the Carboniferous epoch of Europe, of Amphibia which, 

 are analogous to, though altogether distinct from, the " homotaxic " 

 American Labyrinthodonts, — analogous to them in the degree of 

 ossification of the skeleton and development of the limbs, — different 

 from them not only in detail, but in the existence of such types as 

 Opldderpeton and Iclitliyerpeton, which have at present no parallel 

 either in America or elsewhere." 



The discoveries of the last five years show that the Labyrinthodont 

 Amphibia were as largely represented and as well developed in the 

 Carboniferous as in the Triassic formation. Three genera are known 

 from the Permian formation of Europe, and five from Asiatic, African, 

 and Australian rocks of an age which, if not certain, may safely be 

 assumed to be between the Carboniferous and Lower lEesozoic periods. 



Professor Huxley concludes these observations by tbe folloT^dng 

 remark: — *' putting all these facts together, it would appear that 

 the Labyrinthodonts represent the first rope of the bridge which will 

 one day be suspended across the gulf which at present separates the 

 Palaeozoic from the Mesozoic fauna." 



