102 PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 



The measurements are from an individual (No. 15,391) which is some- 

 what larger than the type. 



MEASUREMENTS. 



Upper dentition, length 029 " L , length 002 



" " " -1, inclusive . . . .028 " width 002 



1, length (*'. e., antero-posterior diameter) .003 Skull, length in median basal line 078 



" width (i. e., transverse diameter) 004 " extreme length 092 



*, length 004 Cranium, length to anterior rim of orbit .065 



" width 004 Face, length 03 1 



a , length 005 Occiput, height 032 



" width 004 " width at base 052 



A, length 0045 Zygomatic arch, length 040 



" width 003 Rostrum, width at infraorbital foramen . . .030 



, length 005 " " " anterior end 02 1 



" width 003 Palate, length 034 



, length 004 " width at 5 016 



" width 025 " " "i 021 



PELTEPHILUS FEROX Ameghino. 



(Plate XVI, figs. I, 2.) 



Peltephilus ferox Amegh. ; Rev. Arg. de Hist. Nat., T. I, 1891, p. 327. 

 Peltephihts clarazianus Moreno and Mercerat ; Rev. d. Mus. de La Plata, 

 I, 1891, p. 60. 



Although this species is not represented in the Princeton collection, I 

 am enabled by the courtesy of Dr. Ameghino to figure the beautiful speci- 

 men which he has described. In size, P. ferox is intermediate between 

 P. strepens and P. pumihis, and were size alone to be considered, the 

 species could not be regarded as valid, so great is the variation in this 

 respect. A more important diagnostic character is afforded by the pos- 

 tero-median scute of the cephalic shield, the shape and sculpture of which 

 appear to be quite constant in each species. In P. ferox this plate is 

 both actually and relatively smaller than in P. strepens and is of a differ- 

 ent shape, being considerably shorter and wider and measuring 24 mm. 

 in length and 26 mm. in greatest width. As in the latter species, there 

 is a raised border around the margins of the plate, but the surface is not 

 so rough and has no such irregular depressions and pits. 



The teeth differ in a number of respects from those of P. pumilus. In 

 the upper jaw A is the highest of the series, while in the latter - is the 

 highest ; it also stands well in advance of * and is visible in side-view ; 



