344 SYNOPSIS OF THE VERTBBKATE FAUNA OF THE PUERCO SERIES. 



coucave facet. The tubercalcis, like the olecranon, is elongate. The coi-acoid is dis- 

 tinct but short. The peduncle of the ilium is wide. The odontoid process is rather 

 long and cylindric. There is an entepicondylar foramen, as in Pachysena. 



DisSACOs NAVA.iovius Cope, loc. cit.; Tertiary Vertebrata, PI. XXV c, fig. 1. 



The paradiapophysis of the atlas has the base extended throughout the vertebra 

 anteroposteriorly, and the vertebrarterial canal divides it anteroposteriorly, issuing 

 at about the middle of the superior surface. The atlantal articular surfaces of the 

 axis are distinct from those of the odontoid. The floor of the neural canal has a 

 lovr median convex ridge, vv^hich extends to near the end of the superior side of the 

 odontoid process, from which it is separated, as well as from the articular faces below, 

 by a shallow groove. 



The glenoid cavity of the scapula is an oval, gradually acuminating to the 

 narrow origin of the coracoid. The spine oi'iginates abru])tly a little posterior to the 

 middle line. In the humerus the entepicondyle is of moderate dimensions, much 

 larger than in Mesonyx, but less prominent than in many other Creodonta. Outside 

 the roller of the condyle there is a distinct border facet, rising to its external border, 

 which is present in Mesonyx, but is wanting in Oxygena. The roUei' is distinctly 

 convex. The internal flange is well developed. In the ulna, the olecranon is long, 

 straight and compressed. Its inferior border is of uniform width from below the 

 glenoid surface to the extremity, and is but little in excess of that of the shaft fur- 

 ther forwards. The posterior flange for the humerus is not present on the external 

 side of the glenoid surface. The i-adial facet is not very oblique, and it is followed 

 distally on the external side by a deep groove, which runs out on the external side of 

 the shaft. The latter is marked by a deep and wide longitudinal gutter on its inter- 

 nal side, which is bounded by a narrow edge above, and a wide border below. It 

 runs out on the inner side of the shaft pi-oximally, opposite the middle of the external 

 groove. This gutter is wider and deej^er in this species than in any creodont known 

 to me, excepting the Pachycena ossifraga. The head of the radius is a depressed oval, 

 with three articular surfaces ; a median concave, and a narrower reflected bevel at 

 each end, fitting corresponding faces of the humerus. The inferior ligamentous fossa 

 is wide and shallow. 



The femur is not preserved excepting the head, which shows a rather shallow fossa 

 ligamenti teris, which is well separated from the border. The astragalar face of the 

 tibia is quite oblique, especially next to the fibular suture. The internal malleolus 

 is large, vertical, truncate and furnished Avith a tuberosity in front of the distal 

 extremity. The articular surface is folded back over the anterior edge for a short 



