Hatcher: Fork Limu and Manus of Brontosaurus. 871 



now that the position of each is definitely known, furnish important 

 aid in assigning the various metacarpals when found disassociated to 

 their proper positions. Some of the i)rincipal characters of the meta- 

 carpals are well shown in plates XIX. and XX, and figs. 4, 1 1, and 12. 

 Principal measurements of metacarpals, column i, greatest length ; 

 2, greatest transverse diameter at proximal end ; 3, greatest trans- 

 verse diameter at distal end ; 4, least transverse diameter of shaft. 



T/ie Phala/iges. — The entire series of proximal phalanges are pres- 

 ent as is also the second or terminal phalanx of the first digit. 



The ])roximal phalanx of the first digit is longer on the external 

 than on the internal side, so that when in position between the ungual 

 and Mc. I. it appears wedge shaped, with the wedge directed toward 

 the opposite foot. The internal lateral surface is convex and the ex- 

 ternal deeply concave. The palmar surface is produced posteriorly 

 into a thin sheet which lies under the distal end of mc. I. The 

 proximal articular surface is concave supero-inferiorly and there is a 

 low, broad keel for articulation with the groove in the distal articu- 

 lar surface of mc. I. The distal articular surface is regularly convex 

 supero-inferiorly and concave transversely. 



The ungual of the first digit is compressed laterally but deep pos- 

 teriorly. The internal lateral surface is convex, the external flat. 

 The proximal articular surface has been so much distorted by pressure, 

 due to the position in which it lay when imbedded, that its characters 

 are obscured in the present specimen. The distal extremity is pointed 

 and the entire external surface throughout the distal two-thirds of its 

 length bears evidence of its having borne a powerful claw during the 

 life of the individual. 



