146 



E. C. CASE 



marked by faint rugose ridges concentric around the inner end. 

 Between the two faces and on a level with the posterior the trans- 

 verse process for the rib originates and extends forward and down- 

 ward until the lower end is just above the upper third of the anterior 

 face of the centrum and directly below the anterior zygapophysis. 



On the anterior face of the 

 vertebrae the inner ends of 

 the articular faces of the 

 zygapophyses are continued 

 inward and downward as 

 strong processes which bear 

 on their inner ends the faces 

 of the hyposphene inclined 

 sharply inward and down- 

 ward. These faces are 

 shorter than the zygapo- 

 physial faces, but are fully 

 as deep and as well devel- 

 oped. They form a striking 

 feature of the vertebras. 

 Between the inner ends of 

 the zygapophysial faces is a 

 deep nearly round pit with 

 a rugose bottom. It is 

 directly above the neural 

 canal, from which it is sepa- 

 rated on the face of the vertebrae by a wide V-shaped partition. 

 The posterior face of the inner ends of the zygapophyses are con- 

 tinued downward and inward as strong ridges which separate a 

 deep triangular pit above, in the median line, from the hypantrum 

 faces below. This triangular pit corresponds to the rounded pit on 

 the anterior face, and the two evidently afforded attachment to a very 

 stout ligament which bound adjacent vertebrae together. (Compare 

 Cope's idea of' the external form and habits given below.) The 

 upper end of the neural spine is divided antero-posteriorly by a 

 shallow, V-shaped channel. The anterior and posterior edges of the 

 spine are drawn out into sharp edges, giving the whole a diamond - 

 shaped section. 



Fig. 12. — Anterior view of the seventh pre- 

 sacral vertebra of specimen No. 1077, showing 

 hyposphene and pit above the neural canal. 



