274 ON THE EXTINCT MAMMALIA OP 



Inches. Lines. 



Length in front, from the edge of the carpal articular surface to the 



bottom of the distal median ridge, . . . .10 7 



Breadth of carpal articular surface, .... 22 



Diameter of carpal articular surface from before backward, . 18 



Circumference of shaft at middle, ..... 48 



Transverse diameter of shaft at middle, .... 16 



Antero-posterior diameter of shaft at middle, ... 14 



Breadth of the phalangial articular surface, ... 20 



Antero-posterior diameter of phalangial do. at the median ridge, 17 



25. A mutilated pastern, from the Niobrara River. It is nearly as long as in the 

 recent Horse but of more slender form. It probably belonged to a Hipparion. 

 Its measurements are given in the account of the succeeding specimen. 



26. A pastern and coronet bone, apparently from the same individual, from the 

 Niobrara River. 



The pastern nearly agrees in size and proportions with the preceding specimen, 

 being slightly shorter and narrower. The comparative measurements of the two 

 pasterns are as follow : 



Length, in the axis, 

 Width of proximal end. 

 Width of distal end. 

 Width of shaft at middle, 

 Thickness of shaft at middle, 



The coronet bone is nearly of the size and proportions of the specimen last de- 

 scribed. It measures sixteen lines long, twenty lines in width at the proximal end, 

 and nineteen lines at the distal end. 



27. A coronet and coffin bone, apparently from the same individual, from the Nio- 

 brara River. 



The coronet is longer than in any of the preceding specimens except that of the 

 reconsti'ucted foot, which it approaches very nearly in form as well as size. The 

 coffin bone, on the other hand, is much smaller than in any of the preceding speci- 

 mens, though its articular surface accords in size with that of the coronet just indi- 

 cated. It is further remarkable from the small extent of its lateral angles, which 

 only project slightly beyond the articular border. The length of the coronet is 

 eighteen lines, the breadth of the proximal end twenty-five lines, and of the distal 

 end twenty-four lines. 



The measurements of the coffin bone are as follow : 



Lines. 



Lines. 



. 35 



34 



. 23 



21 



. 18 



18 



. 15 



13J 



. Hi 



12 



