110 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.51. 



(pi. 3, figs. 2, 3) may be compared with that of Burmeister's figure.^ 

 This has a length of 26 mm. and a width of 18 mm. across the middle 

 lobe. In G. j}etaUferus the corresponding measurements are 22.5 mm. 

 and 15.5 mm., the longitudinal measurements being taken at the 

 middle of the width. The height of this tooth is TO mm. in a straight 

 line. In G. asper the axis of each of the lobes is at right angles with 

 the axis of the grinding surface; in G. petaliferus the axis of the 

 anterior lobe is turned pretty strongly forward at its inner end ; that 

 of the second lobe less so; while that of the hinder lobe is turned 

 somewhat backward. In G. asper the second tooth is slightly nar- 

 rower than the fourth, 13 mm. at the middle lobe. 



The skull is badly injured, but important parts remain. The axial 

 bones and the occipital region are gone. The roof and lateral walls 

 of the brain case are present, extending forward to about the rear 

 of the orbit. Between this fragment and that presenting the front 

 of the skull an interval is missing. Superiorly the upper surface of 

 the face is present from a line joining the middle of the orbits, 

 to the nasal opening, except a strip on the left side. The palate 

 (pi. 3, fig. 2) is represented on one side or the other along its whole 

 length. Three upper teeth are present. Parts of the facial portions 

 of each maxilla are preserved ; likewise a part of the left zygomatic 

 arch. Parts of both lower jaws are present, including a portion of 

 each ascending ramus and one condyle and a portion of each hori- 

 zontal ramus, with one tooth. The bones of the skull have united so 

 completely that no sutures are visible. 



The parietal region (pi. 3, fig. 1) is convex from side to side. The 

 surface is uneven and pierced by openings for blood vessels. The 

 width, where least, just behind the orbits, is 95 mm. The width just 

 above the opening of the ear was close to 101 mm. This fragment 

 shows that the roof over the front of the brain and that just behind 

 and between the orbits was occupied by large sinuses. The length 

 of the cavity for the brain, including the olfactory lobe, was close 

 to 100 mm., the width 60 mm. 



The width of the skull taken at the lower border of the lachrymal 

 opening is 118 mm. The height of the upper surface of the face, 

 midway between the orbits, above the midline of the palate is 105 mm. 



The length of the palate (pi. 3, fig. 2), measured from the front of 

 the premaxilse to the hinder nares, was close to 200 mm. The width 

 at the third tooth is 38 mm. ; at the hindermost one, 26 mm. The 

 palate is rough and is pierced by many small and about six large 

 foramina. It differs from that of Burmeister's G. asper ^ in being 

 narrower and in being more contracted between the hinder teeth. In 

 the species just mentioned the width is equal to 0.22 of the length; 

 in G. pefalifenis, to only 0.19 of the length. 



1 Anales Mus. Pub., Buenos Aires, vol. 2, pi. 27, flg. 1. 



