350 SCOTT. [Vol. XI. 



much elevated as in Mosckns or Cervns, but is longer antero- 

 posteriorly ; the inner surface of this prominence bears a facet 

 for the astragalus. The distal astragalar facet forms a broad, 

 flat band, which is connected with the cuboid facet. The 

 latter surface is relatively broader than in the Pecora, but 

 has a much greater dorso-plantar extent than in MoscJuis, 

 the calcaneum not being so suddenly constricted distally as 

 in that genus. 



The astragalus is higher and narrower than in recent Pecora, 

 a primitive character which is repeated in such genera as 

 Gelocus, PcebrotJieruim, etc. The proximal trochlea is widely 

 and deeply grooved, and the external condyle is slightly higher 

 and thicker than the internal, and is separated from the cor- 

 responding distal surface by a much wider interval than in the 

 modern deer ; the sustentacular facet is also relatively narrower 

 than in those animals. The distal astragalar trochlea is not 

 only higher and narrower than in the existing Pecora, but is 

 also differently proportioned. The cuboidal surface, in the 

 first place, is distinctly narrower in relation to that for the 

 navicular. In the second place, the junction of the two facets 

 is marked by quite a prominent angulation, while in the modern 

 forms this is a low, rounded swelling. Poebrotheriiim again 

 agrees with Protoceras in this respect, though the cuboidal 

 facet is broader in the former. 



There would appear to be considerable variation with regard 

 to the coossification of the various tarsal elements. Osborn 

 and Wortman say : " In our young specimen of Protoceras the 

 cuboid and navicular are perfectly free, but in the adult speci- 

 men there is some bony union. The line of junction, however, 

 is clearly indicated by a more or less open suture. What is 

 here said of the cuboid and navicular also applies to the cuboid 

 and ectocuneiform, so far at least as the union of the latter 

 with the cuboid is concerned. There appears to be no ten- 

 dency to bony union of the ectocuneiform with the navicular." 

 In the Princeton collection are feet belonging to individuals 

 which are not only adult but aged, and in none of them is there 

 any ankylosis of the cuboid with the navicular or of the ecto- 

 cuneiform with either. 



