SCOTT: TOXODONTA OF THE SANTA CRUZ BEDS. 
x 57 
only articulation between the scaphoid and lunar, for distally the two 
bones are not in contact at all. Distally, there are only two facets, for 
the trapezoid and magnum respectively, there is none for the trapezium ; 
Fig. 27. Fig. 28. 
Toxodoii burmeisteri: Left manus, dorsum, Nesodon imbricatus: Left manus, dorsum, 
X 5. La Plata Museum. X i- 
the trapezoid surface is quite large and deeply concave, while that for the 
magnum is narrow, oblique, nearly plane transversely and slightly con- 
cave palmo-dorsally. At this point the raised ulnar border of the mag- 
num is wedged in between the scaphoid and lunar, quite separating 
them. 
In Toxodon the scaphoid differs in several respects from that of Neso- 
don; being proportionately narrower transversely, more elongate proximo- 
distally and having a less oblique position in the carpus ; the dorsal face 
forms an irregular pentagon and the palmar protuberance has become 
much larger and more prominent. The proximal facet for the radius is 
more saddle-shaped, much more deeply concave palmo-dorsally, more 
convex transversely and covers the entire proximal end, which, as above 
mentioned, is not the case in Nesodon. The magnum facet is relatively 
wider and more directly distal and the trapezoid facet, which is very 
similar in form, does not extend quite so far proximally upon the radial 
side. 
