64 SCOTT. [Vol. V. 



The metacarpus consists of two functional and two rudimen- 

 tary digits. Mc. II is a short scale which is closely applied 

 to and apparently sometimes even slightly co-ossified with mc. 

 Ill : it articulates with the trapezium and trapezoid, but not 

 with the magnum. Mc. Ill is very long, though relatively 

 shorter than in the recent forms, and very slender, especially in 

 the distal portion. Owing to the different levels at which the 

 distal surfaces of the magnum and the unciform stand, mc. Ill 

 rises higher than mc. IV, and so abuts against the unciform ; 

 on the radial side its head has extended over so as to occupy 

 much of the trapezoid. Mc. IV is a trifle shorter and some- 

 what more slender than No. Ill, but is otherwise shaped like it. 

 The distal ends are very slightly expanded ; the carinae are 

 low and entirely confined to the palmar side. Mc. V is even 

 smaller than No. II. 



The phalanges are very unlike those of the existing species ; 

 those of the first row are not so long, less expanded at the 

 extremities, and more regularly rounded. Those of the second 

 row are short, slender, and rounded : their greatest diameter is 

 from the dorsal to the palmar side. The unguals are long, 

 pointed, and slender, with the medial surfaces flattened ; the 

 external rounded, and altogether much more like the unguals of 

 antelopes or deer than like the nodules of the Tylopoda. 



The skeleton of the John Day genus, GovipJwtJicrium, so far as 

 it is known, does not differ sufficiently from that of PcebrotJierium 

 to require description, and the skeleton of Protolabis is quite 

 unknown. 



The fore limb of Procamclus occidentalis (that of P. angusti- 

 dens is not known) has been described and figured by Cope. It 

 is very like that of the llama, which it about equals in size, but 

 is decidedly more slender. 



In the scapula the spine rises close to the coracoid border ; 

 the coracoid process has very greatly increased in size and mas- 

 siveness, and its free end forms a long recurved hook. 



The humerus has become markedly stouter than that of 

 PcebrotJieriwn, but less so than that of the llama, and the deltoid 

 ridge and hook much more prominent ; the distal end is broader, 

 the supracondylar foramen no longer present, and the inter- 

 condylar ridge broader and more rounded. The external tuber- 

 osity is very much reduced in width, but it still rises high above 



