1913] 



Stock: Noihrotherium and Megalonyx 



347 



in its lower half as in the Brazilian species. A line of small 

 vascular foramina extends from the orbital opening of the infra- 

 orbital canal to a point posterior to the last alveolus. The 

 palate is elongate, slightly convex transversely, and appears to 

 be more strongly pitted than in M. jeffersonii. Posterior to the 

 last alveoli it becomes transversely concave. Anterior to the first 

 alveolus the palatal and lateral portions of the maxillary meet 

 almost at right angles. The tooth rows are nearly parallel. The 

 alveoli, with outer walls somewhat broken, are quadrate in form 

 with rounded corners, as is typical of the genus Noihrotherium. 

 With the exception of the last alveolus their lateral walls are 

 ribbed on the median line. All have the anterior wall concave 

 inwardly and the posterior wall convex, with the exception of 

 the first alveolus, which has its posterior wall slightly concave. 

 The posterior wall of the last alveolus projects below the level 

 of the palate and is continued posteriorly as a strong ridge. 



The lachrymal narrows ventrally as a bluntly rounded exten- 

 sion on the zygomatic process of the maxillary. The lachrymal 

 foramen is just anterior to the middle of the bone. A deep 

 furrow extends downward from this foramen. The jugal was 

 not found with the skull. 



The palatines are narrow and the palatal portion is restricted 

 chiefly to the margin of the postpalatine notch. The post- 

 palatine foramina are much larger in Noihrotherium graciliceps 

 than in the Brazilian species, and the postpalatine notch is more 

 acute anteriorly than in the latter form. The anterior portion 

 of the vomer is broken ; posteriorly it is sharply keeled in the 

 median line, as in Megalonyx jeffersonii, and narrows toward 

 the basisphenoid. In X. escrivanense the keel of the vomer 

 appears thickened posteriorly. 



A portion of the tympanic bulla remains on the right side. 

 Unfortunately its connection with the palatine is too imperfect 

 to show clearly its relation to the pterygoid. Reinhardt states 5 

 that in N. escrivanense the expanded backward projections of 

 the pterygoids form the tympanic bullae. The inner wall of 



s Reinhardt, J., Kaempedovendyr-Slaegten Coelodon, Vidensk. Selsk. 

 Skr., 5 Raekke, naturvidenskabelig og mathematisk Afd., vol. 12, 3, \>. 

 336, Kjobenhavn, 1878. 



