15 



near the posterior extremity, a prominent lrypapophysial keel, 

 and prolonged neural spine. Supposed proximal limb bone with 

 a branch-like trochanter. Supposed teeth in several rows, at- 

 tached in shallow alveoli, those of the marginal series larger; the 

 crowns obtusely conic and simple. 



In the above diagnosis are expressed the general characters of a 

 genus of probably tailed Batrachia which has left remains of seve- 

 ral species in the Judith' River beds of the Upper Missouri region. 

 Although the vertebras resemble no little those of clepsydrops, 

 Cope, a rhynchocephalian lizard from supposed triassic or permian 

 formations, the atlas is that of a batrachian. The limb bone pro- 

 bably belonging to it, is unlike that of any genus of the Proteida 

 or Trachystomata, differing also from that of Menopoma, but 

 approaching nearly that of the typical salamanders. The diapo- 

 physes are different in form from those of the Trachystomata 

 Proteida and Amphiumidse, but resemble in their vertical com- 

 pression those of Menoptoma. They are generally broken in the 

 specimens, but where preserved, are much shorter than in that 

 genus, being even less produced than in most of the recent sala- 

 manders. The prominent keel of the median line below is not 

 found in salamanders, and it has no posterior prolongation resem- 

 bling the structure seen in Amphiuma and Gseciliidee. The 

 produced neural spine is a character not found among tailed 

 Batrachia. and the posterior direction which it takes reminds one 

 of the Brinosauria more than anything else, and is not like the 

 form seen in Lacertilia. It is a prolongation of the roof-like 

 extension of the neural arch seen in some of the tertiary sala- 

 manders of France. 



The structure of the proximal limb bone, and the form of the 

 diapophyses of the vertebrae refer this genus with much proba- 

 bility to the Urodela. The produced neural arch, and the pro- 

 bably complex disposition of the teeth, indicate a family different 

 from any of those now living. The biconcave centra place it 

 nearest to the Amblystomidse. 



The teeth above mentioned are attached to a fragment of a jaw- 

 bone. The crowns are all imperfect, and inostty broken off. There 

 are three series of smaller teeth and a mai'ginal series of teeth of one 

 half greater diameter. They exhibit a moderate pulp cavity, and 

 the superficial investment of the crowns is not inflected. It has a 

 minute granular rugosity, and the bases of the teeth are rugose 



