Cope.J 51b [April. 5, 



Width of neural spine at summit 035 



Length of ilium 120 



This species appears to have been about the size of the Mississippi alli- 

 gator. Unfortunately the cranium is unknown, but probably some of the 

 jaws and teeth in my possession belong to it. 



From the region above already mentioned. 



Metarmosaruus possatus. Gen. et sp. nov. 



Char. Gen. There are numerous vertebrae in the collection, from the 

 median and anterior dorsal parts of the column, which differ from those of 

 Clepsydrops and Epicordylus in their small antero posterior diameter. 

 That these all belong to one species, or even one genus, is not probable, in 

 view of the many differences Avhich they present. I select one of them 

 whose characters are most strongly marked, and designate it as above, with- 

 out deciding as yet, how many of the others which agree with it in some 

 respects, may hereafter be associated with it as to species or genus. 



The centrum is a good deal shorter than wide, and like those of all 

 the other genera here described, is deeply biconcave. I have not yet ascer- 

 tained whether it is notochordal, owing to the state of the specimens. The 

 diapophyses project just below the base of the neural arch, and are short 

 and with small tubercular facet. There is no capitular facet. The facet 

 for the intercentrum is excavated at the anterior .extremity of the base of 

 the centrum and is quite small. The neural canal is rather large. The 

 anterior zygapophyses have a peculiar form, their articular faces being 

 directed downwards and outwards. This character, together with the 

 form of the centrum and intercentrum, distinguishes this genus at once 

 from those previously described. 



Char. Specif. The posterior articular face is a little deeper than wide, 

 and has rather thick recurved margins. The sides are concave, and the 

 middle line below protuberant (in section), but not keeled. The intercen- 

 tral fossa is a transversely oval pit well defined all round, and not inter- 

 rupting the contour of the inferior margins of the articular faces. 



Measurements. M. 



[ antero-posterior. 021 



-r.. , P . transverse behind ' .03C 



Diameter of centrum < 



J vertical " 030 



[ " in front 024 



Width of intercentral fossa 010 



Expanse of posterior zygapophyses 025 



About the size of the Dimetrodon rectiformis. 



Empedocles alatus. Gen. et sp. nov. 



Char. Gen. -This genus is of the same type as those already described 



as allied to Clepsydrops. I know of it from numerous vertebras, but few of 



which belong to any one individual, four consecutive centra being the 



largest number I have obtained in association. The various specimens 



