EDENTATA OF THE SANTA CRUZ BEDS. 31 I 



obscure than in S. fractum ; the postorbital constriction is much shallower 

 and less abrupt than in the latter. The squamosal is long and low and 

 the tubercle at its infero-lateral angle is unusually prominent ; the zygo- 

 matic process is short and weak and near its base is pierced by a vascular 

 foramen. The lachrymal is less prominent than in most of the genera. 

 The facets for the premaxillae on the maxillaries indicate that they were 

 somewhat different from those of Schismotherium ; the surface for the 

 postero-external branch is larger and rises higher upon the sides of the 

 anterior nares and the notch for the spines is deeper and narrower. The 

 preorbital portion of the maxillaries is shorter than in Schismotherium 

 and the fossae deeper than in S. splendens ; the bony palate is of nearly 

 uniform width. The posterior nares differ from those of Hapalops in 

 having lower side walls. 



The mandible resembles that of S. fractum in appearance, but is lighter 

 and more delicate ; the ventral border of the horizontal ramus is but 

 slightly convex ; the symphysis is short and the predental beak is short, 

 narrower and more pointed than in S. fractum ; the ascending ramus is 

 very much thinner than the horizontal, producing a peculiar angulation 

 of the jaw. 



MEASUREMENTS. 



Type. L. P. Museum. No. 15,04.9. No. 15,627 



Skull, length in median basal line .098 



" " condyle to anterior nares .094 .116 .108 



Cranium, length condyle to edge of orbit. .. .089 .080 .098 .089 



Face, length orbit to anterior nares .016 .020 .021 



Occiput, height 030 .028 .035 . .034 



width at base 039 .040 .046 



Cranium, width over zygomata 039 -O39 -47 



" at postorbital constriction .. .023 .024 .031 



Zygomatic arch, length .053 .069 .063 



Palate, length in median line .038 



" width at 1 015 .016 .017 .019 



" " -1 012 .013 .015 .013 



" & OIO .OIO .OI2 .OI2 



In the La Plata Museum is a curious jaw-fragment, evidently patho- 

 logical and probably referable to this species. As the result of inflamma- 

 tion, the horizontal ramus is swollen and pitted on the outer side and the 

 process has given an abnormal character to ^. The anterior half of this 

 tooth, which is considerably narrower than the posterior, is composed of 



