GLIRES OF THE SANTA CRUZ BEDS. 481 



floor of the orbit, and dorsally less of it appears upon the cranial roof; 

 the supramastoid process is both longer and wider, but is less expanded 

 at the posterior end, and there is no such groove above the root of the 

 zygomatic process. The latter process is longer, overlapping the jugal 

 more extensively and articulating with it by a simple, almost straight 

 suture. The jugal is longer and narrower dorso-ventrally, but of similar 

 laterally compressed, plate-like structure ; anteriorly, it ends in a sharper 

 point which penetrates much farther into the zygomatic process of the 

 maxillary, but is farther removed from the lachrymal. The ventral branch 

 of the maxillary zygomatic process is much more slender and is far more 

 deeply notched to receive the jugal. The lachrymal is considerably 

 smaller, but has a similar triangular shape and very low spine. The 

 frontals are broad, moderately convex and smooth, without protuberances 

 for the sinuses ; the orbit is deep and the supraorbital border prominent 

 and may or may not be notched ; if present, the notch is much shallower 

 than in Dolichotis ; the postorbital process, which is incomplete in all of 

 the skulls, may have been no longer than in the recent genus, but is 

 more prominent, being directed outward, instead of downward. The 

 anterior end of the frontal region has simpler sutures than in Dolichotis 

 and there is hardly any nasal process. The nasals are longer than in the 

 modern genus; in breadth and degree of convexity they differ in the 

 various species ; the anterior ends, which are not preserved in any of the 

 specimens, were probably shaped as in Eocardia. 



The rostrum is relatively somewhat shorter and broader and tapers less 

 anteriorly than in Dolichotis, but in the proportions of the rostrum decided 

 differences may be noted between the various species. The premaxillaries 

 are shorter than in the existing genus, but the ascending processes, which 

 articulate with the frontals, are longer. The maxillaries differ from those 

 of the modern genus in several respects : the edentulous portion, in front 

 of the grinding teeth, is longer, making up more of the rostrum, and is 

 more deeply invaded by the much larger incisive foramina ; the masseteric 

 fossa is much deeper, though of similar shape, and the alveolus of m 3 - pro- 

 jects less conspicuously into the orbit. The palate is less triangular than 

 in Dolichotis, but rather more so than in Eocardia, and differs from that of 

 the latter in having shorter palatines and larger maxillary elements. The 

 posterior nares are wider than in Eocardia, with walls diverging more 

 posteriorly ; the pterygoid fossae are large and perforated at the bottom, 



