“1768 BULLETIN OF THE 
and it is therefore unnecessary to dwell upon it here further than to remark 
its very close resemblance in many important respects to the the eocene genus 
Hyrachyus. In general there are also certain analogies with the horse, in the 
delicate head, long neck, and elongated and narrow: feet. 
Hyracodon major, sp. nov. The type of this species is a fairly complete 
skeleton in the Princeton Museum, and in the Cambridge collection it is rep- 
resented by a beautifully preserved fore-foot. Of this the carpus is high and 
narrow ; the scaphoid is less produced laterally than in Aceratherium, the facet 
for the trapezium is very small and infero-lateral in position, those for the 
trapezoid and magnum much larger, and nearly equal in size. The lunar is 
contracted and anteriorly rests only upon the unciform, touching the magnum 
laterally, while in H. nebrascense there is apparently no anterior contact be- 
tween the lunar and magnum. The cuneiform is high and much compressed, 
and the pisiform is short, compressed, and much expanded at the free end. 
The trapezium is a very small bone; it is pushed to the posterior side of the 
trapezoid so as not to be visible from the front, and has no contact with meta- 
carpal II, The trapezoid is well developed, though relatively smaller than in 
the rhinoceros, The magnum is very large, in accordance with the develop- 
ment of the third digit, and is especially elongated in the vertical direction. 
The unciform is very high and narrow, and descends much below the level of 
the other carpals ; owing to this compression the facet for metacarpal III. is 
entirely lateral instead of distal ; there is an unusually extensive contact be- 
tween the unciform and the magnum. 
The lateral metacarpals are slender, narrow, and curved, the median one 
considerably longer and much heavier. Metacarpal IT. abuts against the mag- 
num by a considerable facet, while in H. nebrascense the facet is very small. 
Metacarpal V. is represented by a minute nodular bone, which is attached to 
the unciform and to the ulnar side of metacarpal IV. 
MEASUREMENTS. H. nebrascense. H. mejor. 
Garpas; breadthiy').) 2 eacat- easels ee BAS ee 040 060 
«height median line). to aye Gi! 088 .050 
Untiterm, width: g.acvhih tree Sacneen) oo amen cote eee .023 
es Hicight: 2. fe) gisieelibans aa Pewee Oe 033 
Metacarpalil., lengths Heiget ity lish) ©) ac eh see Pe 115 
STE Hig itis rig end ot tae ei ee Bias .128 
2 TENG sah Se ad al ie baa ee 105 
3 Wie oe co tee ee ee as ee eae OLD — 
Hyracodon (?) planiceps, sp. nov. This large species is distinguished 
from H. nebrascense by its extremely low and broad cranium, which is flattened 
upon the upper surface and entirely lacks the sagittal crest, which is repre- 
sented by two ridges diverging from the supra-occipital border. This flat- 
tening alters the proportions of the occiput and temporal fossa. Comparing 
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