SINCLAIR: MARSUPIALIA OF THE SANTA CRUZ BEDS. 369 
probably sharp. A hood is developed to about the same extent as in 
Borhycena. The subungual processes are large and an ungual foramen is 
present. 
The greater part of both halves of the pelvis is preserved (PL XLIX, 
figs. 3 ; PI L, fig. 1), but, unfortunately, the pubes are almost entirely 
missing. The peduncular portion of the ilium is considerably heavier 
than in Thylacynus , supporting a very large tubercle for the origin of the 
rectus femoris muscle. The gluteal surface is broadly expanded, but with 
little trace of the longitudinal grooving noticeable in the recent genus. 
The ilio-pectineal eminences are very large and rugose. The ischium is 
incomplete posteriorly, lacking the ischial tuberosity, but both acetabular 
and post-acetabular portions are heavier than in Thylacynus. The ischial 
spine is small. The pubis, so far as preserved, is narrower antero-pos- 
teriorly than in the recent genus. The acetabulum is large and deep. 
Beneath the acetabular notch, the border of the obturator foramen is 
exceedingly sharp. Posteriorly, it assumes the usual convex contour. 
The femur (PI. L, figs. 2, 2 a), although of almost the same length as 
in Thylacynus , is much heavier. The large hemispherical head is sup- 
ported on a long neck. The greater trochanter rises above the level of 
the head, from which it is separated by a broad interval. The digital 
fossa is long and deep and the intertrochanteric ridge high and narrow. 
The lesser trochanter is slightly larger than in Thylacynus and is separ- 
ated farther from the head. The shaft is straight, circular in cross-section 
at the middle, but flattened antero-posteriorly at either end. Above the 
condyles, the distal end is semicircular in cross section. The condyles 
have about the same posterior extension as in Thylacynus , but are much 
flatter transversely, resembling Borhycena. The intertrochanteric fossa is 
wider and deeper, and the rotular groove broader and shallower than in 
Thylacynus. 
The patella (PI. L, figs. 4, 4 a) is a stout, wedge-shaped element, broad 
at the proximal end, but tapering distally to a thin edge. The rotular 
surface is irregularly pentagonal in outline, concave in vertical section 
and convex transversely. The anterior surface is rugose for tendinous 
attachment. 
The tibia (Pis. XLIX, fig. 4 ; LI, fig. 2), unlike that of Thylacynus, 
is considerably shorter than the femur. The head supports two broad, 
flat surfaces for articulation with the femoral condyles. The spine is 
