SINCLAIR! TYPOTHERIA OF THE SANTA CRUZ BEDS. 
57 
the trapezoid and the second metacarpal. Distally, it is spherical and 
quite rugose, without the slightest trace of a surface for the pollex. The 
trapezoid, magnum and unciform do not differ sufficiently from those of 
Protypotherium to call for separate description. The metacarpals inter- 
lock proximally to about the same extent and in the same manner as in 
the latter genus. Distally, keels are present on the palmar surfaces. 
The phalanges resemble those of Protypotherium. Slight terminal clefts 
may or may not be present in the unguals, both conditions occurring 
in the same specimen. 
The ilia (PI. VI, figs, n, 12) are long and narrow, with deeply concave 
gluteal fossae, prominent superior and inferior borders and inconspicuous 
spines. The crest of the ilium, as in Protypotherium , is inclined forward 
obliquely. Inferiorly, the ilium is flattened, not excavated longitudinally 
as in the latter genus. The neck is robust, with prominent tubercle for 
the origin of the rectus femoris. Prominent ilio-pectineal eminences are 
developed. The ischia are broadly expanded and fan-like, with scarcely 
perceptible ischial spine. The descending ramus and the pubis are slen- 
der, inclosing a large, oval obturator foramen. The acetabulum is circular 
and deeply cupped, with narrow cotyloid notch. 
The straight femoral shaft (PI. VIII, figs. 3, 4) is more compressed antero- 
posteriorly than in Protypotherium. The head is large and globular, and 
impressed by a deep pit for the round ligament. The greater trochanter 
is low, not exceeding the elevation of the head. The lesser trochanter is 
proportionately larger than in Protypotheriimi and the third trochanter 
quite small and inconspicuous. The distal end is flattened transversely, 
with prominent condyles, of which the inner projects slightly beyond the 
outer. The patellar trochlea is proportionately wider and shallower than 
in Protypotherium. 
The patella (PI. VIII, figs. 29, 30) seems disproportionately large. It 
is almond-shaped in outline, strongly convex in all dimensions anteriorly 
and quite rugose. Posteriorly, the surface for contact with the femoral 
trochlea is slightly differentiated into two broadly concave facets. 
The tibia and fibula (PI. VIII, figs. 5, 6) are quite firmly fused proxi- 
mally, but less completely so distally, where the suture remains distinct. 
The tibial shaft is slightly curved inwardly, the straight fibula spanning 
the arc. Proximally, the tibial articular surfaces are circular and slightly 
concave transversely, with inconspicuous spine. The shaft is triangular 
