140 MEMOIRS OF THE CARNEGIE MUSEUM 
slightly higher than the tibial angle.” The proximal facet for the ectocuneiform is 
slightly concave transversely in the dorsal region, and convex antero-posteriorly in 
the palmar region to conform with the facets of the ectocuneiform already described. 
On the postero-fibular angle of the head is a very minute facet which articulates with 
Mt. II. Below this facet is a rugose shallow channel, which receives the second 
metatarsal. The palmar process is strongly developed, and, as in Archxotheriwm, 
bears three facets; the one on the tibial side is for the entocuneiform, the one on the 
fibular side is for Mt. IV, and the one on the palmar end is for a large sesamoid. 
The facet for Mt. IV, which is near the dorsal face is larger and more pronounced 
in Dinohyus than in the Princeton specimen. The shaft is quite flat, long, and 
slender on the palmar and fibular faces, round on the tibial and dorsal faces, and is 
similar to that of Archxotheriwm, except for its greater rugosity on the fibular face, 
which is a marked character, showing a tendency toward the codssification of the 
two functional digits in Dinohyus. The large tubercle which is developed on the 
fibular border of the dorsal face just above the trochlea in Archwxotheriwm, is in Dino- 
hyus developed into a swollen area which occupies the entire dorsal face of the shaft, 
causing a deep depression distally. This depression is the superior boundary of the 
distal trochlea. The latter is, as in Archxotheriwm, rather low and narrow. The 
carina, which is confined principally to the plantar side, is plainly indicated on the 
dorsal face by a faint ridge, which continues to the extreme proximal border of the 
articulation. On either side of the carina is a shallow depression, which causes a 
slight lateral convexity in the tibial and fibular portions of the trochlea. 
MEASUREMENTS OF THIRD METATARSAL. 
Mm. 
Giteatesti len piles te asecsvaiocsane secascalewi relay ol ger a teerneunntnGnestoieed voketedde se 240 
ge AWCOCO-POSLCLION GIAMElED Ol NCACs waqerhis tests tiny stinsts deavetvtas ox oreo 55 
ee transverse bh a pth: t) 
Antero-posterior diameter of shaft medially. 30 
Transverse it bu UY hogou) 
ee ie PCE AOC LCA eG tamiahin dvr I Saas shiek Bciiicinee Suir wee ate 0a 40 
Antero-posterior i is Gee Apu air cirate caedias erinen ahaa s eels taeons gs tas 45 
Metatarsal 1V. —'The fourth metatarsal is of very nearly the same length and 
thickness as the third. The head does not rise as high as that of the third, but the 
palmar process is, as in Archxotheriwm, longer than that of the third metatarsal. 
Dorsally the articular facet for the cuboid is slightly concave in all directions and 
rises into an antero-posterior convexity in the palmar region. There is a large facet 
for the cuboid on the end of the palmar process ; the tibial face of the process is 
5°Some species of the John Day formation more nearly approach Dinohyus in the matter of the articular 
facets of the cuboid and Mt. III. 
