HAPLODONTIDAI—LIMB BONES OF HAPLODON RUFUS. 581 
and pubic rami enclose a very large obturator foramen, of subtriangular shape, 
but with all the corners rounded off. The “horizontal” and “ descending”, 
in this case nearly anterior and posterior, rami of the pubis, are about equally 
slender, notably more so than the ischium; the descending ramus is ata right 
angle with the ischium. ‘There is a well-developed tuberosity of the ischium, 
but no notch in the bone above it. The pubic symphysis is short, and the 
connection of the bones slight. 
Bones of the hind linb—The femur is a stout straight bone about two 
inches long, the shaft much flattened, the distinction of parts at either extrem- 
ity well marked. The globular head represents more than a hemisphere; it 
stands off from the shaft at an angle of about 45°, upon a constricted but 
short neck. It bears a well-marked pit, denoting the insertion of the liga- 
mentum teres. The trochanter major is very prominent, rising as high as the 
head of the bone, a deep notch intervening; there is a conspicuous fossa on 
its posterior face, while from its outer aspect a prominent ‘‘ gluteal” ridge 
runs nearly half way down the shaft of the bone, like the corresponding 
“deltoid” ridge of the humerus. There isa strongly marked lesser trochanter— 
a tubercle on the postero-internal aspect of the shaft, just below the neck of 
the bone, prolonged downward as a sharp ridge. No third trochanter is 
recognizable. The condyles are well formed; the inner is larger than the 
outer, reaching farther down, especially farther back, and being decidedly 
thicker across; its articular surface is, however, narrower. Behind, the con- 
dyles are separated by a deep notch; in front, a trochlear surface (broad 
groove) for the play of the patella reaches far above the portion of the joint 
which enters into the tibial articulation proper: 
There is a large sesamoid bone in the knee-joint, the pafedia being one- 
third of an inch long, of conico-triangular sbape, with smooth concavo-con- 
vex posterior face for articulation with the femoral trochlear groove which 
surmounts the condyles in front. 
Of the two bones of the crus, the ¢ébéa alone enters into the construction 
of the knee-joint, the head of the fibula being much below the articulation. 
The tibia, as long as the femur or slightly exceeding it in length, is straight 
when viewed from the front, but from the side shows a decided /shape, 
having an anterior convexity above and corresponding posterior bend below. 
The lower half of the shaft is smooth and cylindrical, but the upper develops 
two large crests, one anterior, like the “spine” of the human shin-bone, the 
