306 



PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 



orly, the frontals are less deeply emarginated by the nasals and the nasal 

 processes are extremely short; the forehead is narrower, longer, more 

 lozenge-shaped and very gently concave. The nasals are shorter and of 

 a slightly different shape ; posteriorly they are broader and less pointed 

 and are throughout of more uniform width, though the anterior ends are 

 slightly broadened, extending somewhat beyond the maxillaries, and have 

 very wide, shallow notches, with hardly perceptible median point. The 

 maxillaries have better defined and larger preorbital fossae than in S. 

 fractum and the median notch of the palate for the premaxillary spines 

 is broader and shallower; the palate is somewhat narrower and more 

 convex behind than in the latter species and widens more anteriorly. 



MEASUREMENTS. 



Skull, length in median basal line 



" condyles to anterior nares 



Cranium, length condyle to anterior edge of orbit. . . . 



Face, length orbit to anterior nares 



Cranium, width at zygomatic processes 



width at postorbital constriction 



Occiput, width at base 



Rostrum, width at infraorbital foramen 



" " anterior end 



Zygomatic arch, length 



Palate, length in median line 



width at 1. . 



" 3. 



" SL 



Type. 

 .100 

 .118 



093 

 .027 

 .051 



033 

 .046 

 .030 

 .025 

 .065 



.015 

 .012 



No. 9,247. No. /5,jpo. 

 .101 

 .119 



.095 

 .027 

 .044 

 .029 

 .046 

 .032 

 .027 

 .066 

 .040 



.021 

 .OI4 

 .0095 



.026 

 .044 

 .030 



.031 

 .028 



039 

 .OI9 

 .OI4 

 .Oil 



The atlas is higher and narrower proportionately to length than in 

 Hapalops; the anterior cotyles are very small and are given a kidney- 

 shape by a sulcus which invades each from the mesial side, and the pos- 

 terior cotyles are extremely narrow; the neural arch is broad, thin and 

 strongly upcurved, making the canal very high, and has no spine ; the 

 inferior arch is narrower, straighter and without hypapophysis. 



The ulna is relatively longer and more slender than in Hapalops 

 and has a shorter olecranon and shallower sigmoid notch ; the shaft is 

 straighter and the distal end larger, with a projection for the radius which 

 is not present in the genus last named. 



The fibula is remarkable for the antero-posterior extension of the prox- 

 imal end and the large size of the tibial facet ; the shaft is laterally com- 



