182 REPORT — 1841. 



reptiles; others by biconcave joints, as in a few recent and most extinct 

 Saurians. Some species have ribs, others want those appendages ; the pos- 

 session of ribs, therefore, even if longer than those of the CcBcilicB, by a 

 fossil reptile combining all the essential Batrachian characters of the skull, 

 would not be sufficient ground for pronouncing such reptile to be a Saurian. 

 Much less could its Saurian nature be pronounced from the circumstance of 

 its possessing large conical striated teeth ; as the ordinary characters of size, 

 form, number, and even presence or absence of teeth, varies much in existing 

 Batrachians, the location of teeth on the vomerine bones being the only con- 

 stant dental character in which they differ from all other orders of reptiles. 



My first acquaintance with the remarkable fossils under consideration was 

 founded on the examination of portions of teeth, from the new red sandstone 

 of Coton End quarry, Warwickshire, transmitted to me by Dr. Lloyd of Lea- 

 mington. The external characters of these teeth corresponded with those 

 which had previously been discovered, by Prof. Jaeger, in the German Keuper 

 formation in Wirtemberg, and on which the genus Mastodonsaurus had been 

 found. 



The results of a microscopic examination of the teeth of the Mastodon- 

 saurus from the German Keuper, and of those from the New Red Sandstone 

 of Warwickshire, have been detailed in the Proceedings of the Geological 

 Society, January 1841, and illustrated in my ' Odontography,' pp. 195 — 217, 

 pis. 63, 63 A, 63 B, 64, 64 a, 64 b. They proved that the teeth from both 

 localities possessed in common a very remarkable and complicated structure, 

 to the principle of which, viz. the convergence of numerous inflected folds of 

 the external layer of cement towards the pulp-cavity, a very slight approach 

 was made in the fang of the tooth of the Ichthyosaurus, and that a closer ap- 

 proximation to the labyrinthine structure in question was made by the teeth of 

 several species of fishes, while the teeth of existing Batrachians were simple, 

 like those of most Saurians. 



Thus, inasmuch as the extinct animal in question manifested in the intimate 

 structure of its teeth an affinity to fishes, it might be expected that, if it actu- 

 ally belonged to the class of reptiles, the rest of its structure would manifest 

 the characters of the lowest order, viz. the Batrachia, the existing members of 

 which pass, though not by the dental character alluded to, yet by so many 

 other remarkable degradations of structure, towards fishes. Now it has actu- 

 ally happened that, in the same formation in Wirtemberg from which the la- 

 byrinthic teeth of the so-called Mastodonsaurus have been derived, a frag- 

 ment of the posterior portion of the skull has been obtained, showing the 

 apparent absence of the basi-occipital, and the development of a separate 

 condyle on each ex -occipital bone; whence Prof. Jaeger, recognizing the 

 identity of this structure with the Batrachian character above mentioned, 

 founded upon the fossil a new genus of Batrachia, which he called ' Sala- 

 mandroides giganteus.' Subsequent discoveries, however, satisfied the Pro- 

 fessor that the bi-condylous fragment of skull, representing the genus Sala- 

 mandroides, belonged to the same reptile as the teeth, on which he had founded 

 the genus Mastodonsaurus. But notwithstanding the evidence thus olitained 

 of the Batrachian affinities of the Keuper Reptile, Prof. Jaeger preferred to 

 retain for it the name which implied its membership with the Saurian order, 

 and cancelled the genus Salamandroides, Avhich form of substantive has, in- 

 deed, been forbidden by the canons of botanical nomenclature to be used as 

 the name of a genus*. 



I proceed now briefly to notice the fossils from the Warwick sandstone 



* " Nomina generica in o'ides desinentia e foro Botanico releganda sunt." — Linnaei Plii- 

 losophia Botanica, 1751, p. 161. 



