PETERSON: A REVISION OF THE ENTELODONTID® 141 
occupied by the facet for Mt. III; and immediately behind and at almost right 
angles is a third facet, which corresponds to that on Mt. II] and which supports a 
palmar sesamoid. There is no evidence of a facet for Mt. V on the fibular angle of 
the head. Dorsally the shaft is quite flat on its dorsal, tibial, and fibular faces, 
while the palmar face is unevenly rounded. Towards the distal end the shaft is 
more cylindrical, the palmar face being by far the flattest. Distally the bone is 
similar, including the trochlea, to that of the third metatarsal. 
MEASUREMENTS OF FourTH METATARSAL. 
¥ Mm. 
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ie antero-posterior diameter of head... 59 
Me transverse es ee 41 
uh ol “ shaft medially 28 
Antero-posterior ig Ra Mu 32 
if Per SURO CIN Gts 5 vasah oe Seca ie Setaee eee cette 33 
‘Transverse ie KD OU TA Sess cu ato Nee MRRN ti elie asa 37 
Metatarsal V. — Judging from the total absence of facets for the fifth metatarsal 
on the cuboid and Mt. IV it would seem that this element is entirely wanting in 
Dinohyus. There is, however, a minute scale-like eminence on the fibular angle on 
Mt. IV, which may, or may not, represent the fifth metatarsal. 
A water-worn fragment of a fourth metatarsal which I refer to Dinohyus (No. 
1927, Carn. Mus. Cat. Vert. Foss.) was found in the Agate Spring Fossil Quarry, 
No. 1, where the type of Dinohyus was found. On the postero-fibular angle of the 
facet for the cuboid of this metatarsal the articulation is flexed downward in such a 
manner as to suggest the presence of a small fifth metatarsal in this individual. 
Palmar Sesamoid. — The palmar sesamoid is a large bone, triangular in outline, 
compressed antero-posteriorly, and much expanded, especially in the tibial and 
distal directions. The palmar surface is rugose and on the dorsal face near the 
fibular angle are two facets for the third and fourth metatarsals described above. 
There are facets on the palmar processes of the metatarsals in Archxothervwm which 
indicate the presence of similar sesamoids. 
MEASUREMENTS OF PALMAR SESAMOID. 
Mm 
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“ UES VOUS O Fen net oaiteae: ehaesilc ao pucet, recbatbedt urememiettannd racvag st cmtecs 
ey antero-posterior diameter 
Phalanges. —The proximal and median phalanges are proportionately longer 
and narrower than those of the manus; otherwise they are similarly depressed 
antero-posteriorly and expanded transversely. The articulation for the metatarsal 
