NOTES ON THE CANIDH® OF THE WHITE RIVER OLIGOCENE. 397 
toward the fibular side of the foot, making the tibial border somewhat concave. ‘The 
length of the bone, as already intimated, is not determinable, but the portion preserved 
in one specimen is nearly as long as the entire fifth metacarpal of the same individual. 
The second metatarsal is much stouter than the first and more slender than the 
third. The head is very narrow, being slightly excavated on the tibial side. Owing to 
the shortness of the mesocuneiform, the head of mt. 11 rises above the level of mt. i 
and iii and is firmly held between the ento- and ectocuneiforms, though there are no such 
distinct lateral facets for these tarsals as we find in Canis ; a stout prominence occupies 
the plantar side of the head. The shaft is slender and of oval section, not having 
acquired the trihedral shape characteristic of the recent dogs. 
The third metatarsal is the stoutest of the series; the head is broad dorsally but 
very narrow on the plantar side, where there is a large, projecting process, more promi- 
nent than in Canis. The facet for the ectocuneiform is convex (in the recent dogs it is 
slightly concave) and oblique in position, inclining downward toward the tibial side. 
Deep sulci invade the head on both sides; on the tibial side the sulcus is narrow, but 
that on the fibular side is broad. A deep pit on the fibular side of the head receives a 
corresponding prominence from mt. iv, and an additional facet for the same metatarsal is 
found on the plantar projection, so that the two median metatarsals are very firmly inter- 
locked. The shaft, for most of its length, is of transversely oval section, very different 
from the squared, prismatic shape seen in Canis, though an approximation to this shape 
occurs in the proximal portion of the shaft, where mt. iii and iv are closely appressed. 
The distal end is broadened and antero-posteriorly compressed ; the trochlea resembles 
that of the corresponding metacarpal, save that it is larger and relatively somewhat 
lower. 
The fourth metatarsal is of nearly the same thickness as mt. ili, though a trifle 
more slender. The head is narrow and the facet for the cuboid is slightly convex in 
both directions ; the plantar extension is neither so broad nor so prominent as in Canis. 
On the tibial side is a rounded protuberance, which is received into the depression 
already mentioned, in the head of mt. iii, while on the fibular side is an exeayation for a 
prominence on mt. v, and proximal to this excavation is a narrow but well-defined facet 
for the same metatarsal. Very little of the shaft is preserved, and this proximal por- 
tion has much the same tetrahedral shape as in the recent dogs. Doubtless, however, 
the distal part of the shaft assumes a transversely oval section, as does that of mt. iu, 
though the digits of the pes evidently diverge less distally than do those of the manus. 
The fifth metatarsal is entirely missing from all of the specimens, so that the inter- 
esting question regarding the reduction of the external ascending process cannot be 
answered, 
