aesinoitheeitjm:. 



45 



of the rest of this surface articulated with the lunar (lu.), though, as above mentioned, 

 a narrow strip on the outer side was probably overlapped by the cuneiform ; in no 

 specimen of the magnum, however, have actual traces of this overlap been observed. 

 The surfaces for the trapezoid on the one hand, and for the unciform (unc.) on the 

 other, are similar : each consists of a facet which extends the whole depth of the bone 

 in front, but is confined to the upper half posteriorly, the ventral portion of the 

 posterior part of the bone being pinched up into a rounded and backwardly 



Text-flg. 23. 

 A. 



^ 1. 



c. 



Left magnum of ArsinoitTierium zitteli : A, unciform face ; B, from above ; O, from below. 

 lu., facet for lunar ; mc. 2, me. 3, facets for the second and third metacarpals ; sc, facet for scaphoid ; 



unc, facet for unciform. 



I nat. size. 



projecting knob. The distal surface [mc. 2 and mc. 3) is nearly triangular, the 

 posterior angle extending on to the narrowed posterior region just referred to. In 

 some specimens a small area at the antero-internal angle (mc. 2) of this surface is 

 marked off from the rest, and indicates that the articulation of the second metacarpal, 

 in some cases at least, extended slightly on to the magnum. 



The unciform (text-fig. 24) is a wedge-shaped bone, the base of the wedge being the 

 inner surface articulating with the magnum (mag.), the facet for which is nearly 

 flat and extends the whole depth of the bone in front, but is confined to the upper 



