536 . Mr. Owen on species of 



of the German Keuper in their essentially Batrachian nature ; for the well-marked 

 and peculiarly complicated character of the dental structure admits of no doubt 

 that the gigantic species of the Keuper-schiefer, with its Batrachian double con- 

 dyle, is at least generically related to the Labyrinthodons of our own sandstones. 

 With the deviations from the ordinary Batrachia manifested in the dental struc- 

 ture, and in the Crocodilian modifications and sculpturing of the cranium, it 

 might reasonably have been anticipated that corresponding peculiarities should 

 exist in the locomotive extremities, and fortunately we obtain a clue to this part of 

 the organization of lost species by data independent of the osseous remains and 

 more copious in the particulars which they reveal. 



The New Red Sandstone has of late years contributed to the ichnological de- 

 partment of the history of extinct animals one of its most remarkable and pro- 

 blematical examples, in the footsteps of the so-called Cheir other ium. Without reca- 

 pitulating the various conjectures to which these impressions have given rise, I 

 may observe, that, adopting the opinion of Dr. Buckland and other distinguished 

 geologists, that they were the foot-prints of an animal and not vegetable impres- 

 sions, I have long entertained the opinion, and have expressed it in my lectures, 

 that they were the foot-prints of a reptile and not of a marsupial or other mammal, 

 and that this reptile most probably belonged to that family of the class which 

 includes the Frog and other anourous Batrachia which offer a similar disproportion 

 between the fore- and hind-legs. But, on the supposition of the Cheirothere being 

 a Batrachian, it was not less evident that it was quite pecuhar and distinct from 

 any known Batrachian or other reptile in the form of its feet. The analogy of the 

 Crocodilian reptiles would indicate the short and freely-projecting digit to be the 

 outer or fifth toe, whilst the closer correspondence of the Batrachian feet would 

 prove it to be the inner or first toe ; but the thickness, relative size and position of 

 the remaining toes are peculiarities of the Cheirotherian footsteps. 



In the Lahyrinthodon, however, we have a Batrachian reptile, and one that differs 

 very remarkably from all known Batrachia and every other reptile in the structure 

 of its teeth : it is also a Batrachian, which, with strong affinities to the Sauria, ap- 

 pears to have presented the same inequality of size between the fore and hind 

 extremities as does the so-called Cheirothere : and both the footsteps and the fossils 

 are peculiar to certain members of the triassic formations. May we not then be 

 justified, upon this evidence, in adding the name Cheir other ium to Mastodonsaurus 

 and Phytosaurus among the synonyms of the genus Labyrinthodon ? 



I have already alluded to footsteps of a different but somewhat allied form, as 

 being probably those of the Lab. leptognathus. These footsteps actually occur 

 associated with those of the Cheirotherium on the same slab, in the sandstone quar- 

 ries at Storeton, but are more Crocodilian in their character. 



