304 
A MEMOIR UPON THE GENUS 
The cuneiform-unciform facet is triangular in outline, the widest portion 
Magnum —The anterior face of the magnum m P. pahidosus is pentagonal m 
outline being very broad transversely. The form of this bone differs radically from 
that of Umnohyops, in which it is much higher and narrower than m this species, 
thus resembling Hyrachyus which has also a high, narrow magnum. The magnum 
in P. paludosus resembles closely that of Titanothernim, as its general form and 
arrangement of the fiicets are nearly the same as in that genus. 
The relations of the magnum to the other bones of the carpus in Hus species 
are very different from those of recent forms, and when we compare its position 
in the carpus of Tapirus with its place in Palceosyops, the striking difference in its 
size and plane of articulation is apparent. The plane of the magnum-scaphoid facet 
is very oblique, being broad in front and narrowing posteriorly as it ascends upon 
the pivot of the bone ; it is taken up entirely by the scaphoid, ofiering no articula- 
tion for the lunar. The external face of the magnum forms a right angle with its 
superior face. The anterior part of the external face is perfectly plane, and is sub- 
divided equally for the lunar and unciform. Thus the magnum and unciform 
have quite a broad surface of contact anteriorly, which is very nmeh reduced in 
Limnohyops. In Titanotheriiim we find about the same relations between these 
three carpal elements as in this species. In Tapirus on the contrary, the external 
facet of the magnum is wholly taken up by the unciform ; and the lunar being 
crowded out, as it were, from this articulation presents a nearly plane surface of 
contact for the magnum and unciform. The articulation ol the magnum-metacar- 
pal III facet in this species is triangular in outline. This articulation is placed 
rather obliquely and internally and is produced by the large facet developed 
on metacarpal III for the unciform. The magnum-metacarpal II facet is nariw 
and produced far posteriorly. It forms an angle with that for the trapezoid. The 
pivot of the magnum is very strongly developed in this species and rises lugh above 
the plane of the anterior face. 
Unciform. — The unciform is another characteristic bone in the carpus of this 
species. It is very heavy, with a long transverse diameter. Its vertical axis is 
equal to about one-half the transverse. The shape of the unciform differs very 
much from that of Tapirus and Rhinoceros.^ as in these forms the transverse 
