504 Mr. Owen on the Labyrinthodons 



The extremity of the portion of matrix, moulded to the bottom of the socket, having 

 been mistaken for the grinding surface of the tooth, suggested, from its presumed 

 adaptation to crush vegetable substances, the name of Phytosaurus. One of the 

 supposed teeth of this reptile has been transmitted to me by Prof. Jaeger, vs^hich, 

 upon examination, proves to be a mineral cast. 



With respect to the term Mastodonsaurus, it has been already objected that it 

 unavoidably recalls the idea of the Mammalian genus Mastodon, and not the teat- 

 shaped tooth assumed to be the distinctive character of the genus which the name 

 was invented to express. But there are other and graver objections to the term 

 Mastodonsaurus : the rounded and obtuse summit of the crown is an exceptional, 

 not a constant termination of the teeth of this genus, for every tooth in the jaw is 

 originally, and the greater number are permanently, of a cuspidate and not of a 

 mammilloid form. And if the first part of the compound name Mastodonsaurus thus 

 conveys a partly erroneous idea of the dental characters of the extinct genus so 

 designated, the second element — saurus — is still more objectionable, as being indi- 

 cative of a wrong affinity ; since the genus belongs, not to the Saurian, but to the 

 Batrachian order of reptiles. The skull, for example, is joined to the atlas by two 

 condyles developed from the lateral occipitals, and the bony palate is formed chiefly 

 by a divided vomer, supporting teeth. 



Conceiving these objections to be valid for the rejection of the name proposed by 

 the respected Palaeontologist of Stuttgard, to whose assiduous researches our know- 

 ledge of the present most extraordinary Batrachian genus is due*, and believing 

 that I have discovered the true and peculiarly distinctive dental characters of the 

 reptilian genus in question, I propose to designate it by the term Labyrinthodon. 



With respect to this very characteristic fossil of the German Keuper sandstone, 

 it is to be regretted that, with the exception of the teeth, and a fragment of the 

 skull determining its Batrachian character, only a few broken vertebrse have 

 hitherto been found in the Continental formations ; certainly nothing approaching 

 to an entire skeleton. 



On the other hand, the reptilian remains in the Warwick sandstone are still 

 more scanty ; a few teeth, or fragments of teeth, are the only fossils from which I 

 have as yet been able to decide upon the presence of the existence of reptilian ver- 

 tebrated animals in that secondary formation. Hitherto no portion of the cranium 

 corresponding with that which yields the Batrachian character of the Salaman- 

 dro'ides of the German Keuper has been found, and the teeth, therefore, are the only 

 fossils on which any comparison likely to solve the question of identity or other- 



* Ueber die fossilen Reptilien, welche in WUrtemberg aufgefundeii worden sind. 4to. 1828, pp. 35, 

 38, tab. 4 & 5. 



