19 



relatively small vertical diameter, and the longitudinal perforation 

 enters below and before the base and not behind it. The longitu- 

 dinal ridge from the inferior part of the latter is very prominent 

 and horizontal, bridging over the vertical perforation, which enters 

 the superior lateral fossa. It is separated below from the posterior 

 perforation by a short oblique bridge. The neural arch is lost 

 from this specimen. 



There are other vertebrae which display a slightly developed in- 

 ferior keel, and articular cups little produced downwards, but the 

 fossa? are less developed than in the one described. 



Measurements. m. 



/ antero-posterior 006 



Diameter of centrum < vertical 004 



'transverse 003 



The typical individual was about as large as the Menopoma. 



HEMITRYPUS, Cope. 



Represented by a vertebra of the general character of those of 

 the genus Scapherpeton, but which lacks the foramen chorda? 

 dorsalis of the posterior half of the centrum, and is not carinate 

 on the inferior surface. The diapophysis is directed backwards 

 just below the posterior zygapopl^sis, inclosing with it a notch 

 into which the anterior zygapophysis is received. Anterior zj r ga- 

 pophyses connected by a prolongation of the neural arch. 



I had suspected that this vertebra might be one of those of the 

 cervical region of a species of Scapherpeton, but the position of 

 the foramen chorda? dorsalis renders this highly improbable. The 

 only position to which it could be assigned in the column of this 

 genus would be that of the axis. But the foramen is present in 

 the posterior half of the atlas and thus probably in the axis in 

 Scapherpeton, as in vertebra? from all other regions of the column, 

 so that such an exception as is presented by the present centrum 

 is not to be looked for. The absence of the carina, and the cylin- 

 dric form of the centrum, add to the belief that the species does 

 not belong to Scapherpeton. 



Hemitrypus jordanianus, Cope, sp. nov. 



No emargination between the anterior zygapophyses ; neural 

 spine directed upwards and backwards. The diapophyses verti- 

 cally compressed, directed downwards, inwards, and backwards, 



