326 PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 



double. The hard palate is long and narrow, with posterior convexity less 

 marked than in the preceding genera, and the whole palate is less rugose 

 and has far fewer vascular perforations than in the latter ; anteriorly, on 

 each side of the median line and opposite the caniniform teeth, is a fora- 

 men continued forward by a well defined groove almost to the border 

 of the palate. The palatines contribute but little to the hard palate, ex- 

 tending to a line opposite the middle of - and much narrowed by the 

 broad alveolar processes of the maxillaries. The posterior nares do not 

 extend so far forward as in most of the contemporary Gravigrada, the 

 front margin being a little behind - ; the ventral border of the walls of 

 the canal is thickened throughout. The short and narrow pterygoids 

 are not entirely concealed by the alisphenoids, a narrow strip appearing 

 externally behind the latter ; they end ventrally in tubercles which form 

 projections on the inner side and hinder border of the narial canal. 



MEASUREMENTS. 



Skull, length in median basal line 189 Rostrum, width at preorbital fossae 046 



" " condyle to anterior nares . .223 " " anterior end 041 



Cranium, length condyle to edge of Distance, occipital condyle to glenoid 



orbit 153 cavity 03 5 



Face, length orbit to anterior nares 071 Distance, occipital condyle to &- 093 



Occiput, height 064 Zygomatic arch, length 119 



" width at base 074 Palate, length in median line 078 



Skull, width at postorbital constriction. .054 " width in front of 1 037 



" " over lachrymals 084 " at ^ 023 



Forehead, width 073 " " " &- 021 



PLANOPS LONGIROSTRATUS Ameghino. 



(Plate LIX, Figs, i-i 6 .) 



Planops longiro stratus Amegh. ; Enumeracion sistematica, etc., 1887, 



p. 23. 

 Schismotheritim intennixtum Mercerat, in part; Rev. del Museo de La 



Plata, T. II, 1891, p. 8. 



The skull in the Brown collection of the American Museum of Natural 

 History agrees very well with the type of P. longirostratus in the La 

 Plata Museum and also with the specimen which Ameghino has figured 

 ('94, 164, fig. 63), but is much better preserved than either; the parietals, 

 occiput, basis cranii and mandible are lacking, but otherwise the skull is 

 in an excellent state of preservation. 



