Peterson: The Osteology of Promerycochoerus. 193 



cave antero-posteriorly to about the same extent as in Merycoidodon 

 culbertsoni. The posterior hook is more deeply excavated above the 

 base and the rugose surface continues upwards and inwards forming a 

 heavier angle than in Merycoidodon. The anterior face is quite rough 

 distally with a more than ordinarily projecting border at the lower 

 margin, causing a vertical concavity on this surface. Distally the 

 cuboid is taken up almost entirely by the facet for Mt. IV, while that 

 for Mt. V occupies a rather small portion of the external plantar border. 

 This latter articulation is entirely distal, though with a less angular 

 and overhanging external border than in Merycoidodon culbertsoni. 

 The coossified ecto- and meso-cuneiforms are similar in all respects to 

 those of P. montanus. The ento-cuneiform has considerable height, 

 is large, irregularly rounded, and articulates with the navicular, meso, 

 cuneiform, and Mt. II in such manner as to completely interlock the 

 proximal end of the latter. The metatarsals are short and heavy, but 

 longer than the metacarpals. The most striking features are the 

 relatively small reduction in size and length of the second and fifth 

 metatarsals, somewhat as is the case in those of Agriochcerus major 

 described and illustrated by Wortman (I. c, pp. i68, 170). Meta- 

 tarsals IT and V are subequal in length; Mt. II, which is only 12 mm. 

 shorter than Mt. Ill, is slightly the longer, a reversal of what seems 

 to be the case in P. montajtns (/. c, p. 161) and most members of this 

 family, Mt. V being generally the longer. In Siis scofa also Mt. V is 

 longer than Mt. II, while in Hippopotamus Mt. II is slightly longer- 

 The second metatarsal has a strongly curved shaft so that the distal 

 end lies plantar to Mt. Ill when the bones are in position, quite 

 like what is observed in the recent pigs and Hippopotamus. Proxi- 

 mally Mt. II is, as stated above, quite completely interlocked by Mt. 

 Ill externally, by the entocuneiform internally, and by the united 

 meso- and ecto-cuneiform superiorly. With relation to the median 

 metatarsals the length and other proportions of Mt. II and V are, as 

 in the manus, greater than in Merycoidodon culbertsoni, and perhaps 

 more nearly approach the conditions found in the hippopotamus. 

 Mt. Ill is heavy and relatively much shorter than that in Merycoido- 

 don. The head has a broad plane surface for the ecto-cuneiform above, 

 the usual interlocking facets for Mt. IV externally, and a smaller 

 facet for Mt. II internally. The palmar process, though quite promi- 

 nent, is not so large as that on Mt. IV, and, as usual, the tibial and 

 fibular faces overhang only slightly. The shaft is flat, rather straight, 

 and distally there are only slight tuberosities internally and externally, 



