SYSTEMATIC REVISION OF THE SUBORDER. 



65 



Metamosaurus fossatus Cope (text-figures 18 and 19). 



Proc. Am. Phil. Soc, vol. xvii, 1878, p. 516. 



Type: Several vertebrae, one only perfect and showing characters. No. 40 11 

 Am. Mus. Nat. Hist., Cope, coll. ; from Texas. 



Original description : '■'■Char. Gen. — There are numerous vertebrse in the collec- 

 tion, 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 which they present. I select one of them whose characters are most 

 strongly marked, and designate it as above, without 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 ascertained 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. 



"■Cliar. Specif. — The posterior articular face is 

 a little deeper than wide, and has rather thick re- 

 curved margins. The sides are concave, and the 

 middle line below protuberant (in section), but not keeled. The intercentral fossa is 

 a transversely oval pit well defined all around, and not interrupting the contour of the 

 inferior margins of the articular faces. 



Measurements. 

 Diameters of centrum: in. Diameters of centrum cont'd : m. 



Antero-posterior 0.021 Vertical in front 0.024 



Transverse behind 030 Width of intercentral fossa 010 



Vertical behind 030 Expanse of posterior zygapophyses 025 



"About the size of the Dimetrodon rectifor^nis.'''' 



This vertebra is so far from unique in its general form and proportions 

 that it might be a posterior lumbar of two or three separate genera, but 

 the position of the anterior zygapophyses is unlike anything else in the 

 Permian collections. The vertebra is not crushed and the character of the 

 zygapophysial faces seems perfectly natural. There is no appearance of a 

 pathological condition. 



Embolophorus frltlUus Cope (plate 27, fig. 10). 



Proc. Am. Phil. Soc, vol. xvii, 1878, p. 518. 



Type : Two minute vertebrae in position and complete with intercentrum and 

 ribs in position. No. 4010 Am. Mus. Nat. Hist, Cope, coll. ; from Texas. 



flB 



1 8. — Vertebrae of Metamosaurus fossatus, lateral 

 view. No. 4011 Am. Mus. y. %. 

 Fig. 19. — Anterior view of the same, X ^. 



