136 MEMOIRS OF THE CARNEGIE MUSEUM 
The plantar hook is quite prominent and extends well below the distal facets, 
while in Archxotheriwm it is much reduced, and is, as Professor Scott states, ‘ hardly 
more than a roughened ridge.” The anterior portion of the distal face is taken up 
by the facet for the ectocuneiform. The latter facet is divided into two areas by 
fibular and tibial sulci leaving a narrow isthmus midway between the two. The 
small facet for the mesocuneiform, on the tibial angle in Archxotherium, is entirely 
absent in Dinohyus. Another interesting difference in Dinohyus is seen in the very 
much less prominent tubercle on which the facet for the entocuneiform is located ; 
the facet being almost on the same level with that for the ectocuneiform, and sad- 
dle-shaped, with the posterior margin deflected on the base of the plantar hook. 
The navicular of Mntelodon magnum (88, Pl. XX VII, figs. 34 and 37) is rela- 
tively shorter antero-posteriorly, and has a less developed palmar hook than in 
Dinohyus. In Sus the navicular is quite different, being broad and articulating dis- 
tally with the three cuneiforms, as is also the case in Hippopotamus. In the latter 
genus, however, the navicular has no palmar hook, and the articulating surface 
between the navicular and cuboid is situated near the palmar face. 
MEASUREMENTS OF NAVICULAR. Mm. 
Greatest anteror-posterior diameter 
66 
transverse & 
“¢ . vertical “¢ anteriorly 
c 6c be 
posteriorly 
Entocuneiform.— Unfortunately the entocuneiform is lost in the type. Judging, 
however, from the space on the nayicular, and cuneiform when in position, this bone 
was of considerable height, rather compressed trans- 
versely and antero-posteriorly, and in general appar- 
ently somewhat different from that in Archexotherium. 
An entocuneiform of Dinohyus (No. 2139a, 
Carn. Mus. Cat. Vert. Foss.) which was found in 
quarry No. 1, section 20 (See plan of quarry, Pl. 
LIV), is of an animal of approximately the same 
size as the type specimen. ‘The bone differs some- 
what from the corresponding bone in Archezothe- 
riwm, being dorsally less produced and more de- 
Fic. 80, (1) External View of RightEn- Veloped in the palmar direction ; it is not pointed 
tocuneiform of A. ingens Leidy (Princeton (listally, and its navicular articulation is less ob- 
Museum, No. 10885). (2) Same View of 
Corresponding Bone in D. hollandi Peterson 
(Carn. Mus. Cat. Vert. Foss., No. 21392). two facets, one near the proximal end for the 
lique. It is further to be observed that there are 
