308 
A MEMOIR UPON THE GENUS 
tlian the head, and the anterior one is ninch reduced. The fossa between the 
two divisions of the trocRanter is absent in Tapirus. An exaggerated form of the 
.rreat trochanter of P. paludosus is seen in Eqims, but in the latter form the posterior 
hook-like process is placed nearer the head than in P. paludosus. The trochanteric 
fossa is deep, broad, and bordered externally by the prominent rim of the great 
trochanter. 
The anterior surface of the shaft below the head is strongly triangular in out- 
line, becoming deeply concave at each side and above the lesser and third trochan- 
ters! The anterior surface of the shaft below the trochanters is strongly convex 
and its surface narrows below the third trochanter. The lesser^ trochanter is 
proniiiient, compressed and very much elongated ; it extends posteriorly to a hori- 
zontal line cutting the third trochanter near its middle. The third trochanter in 
its large size is in strong contrast to that of the Tapir, where it is very much smaller 
than in Palceosyops. The third trochanter is placed at about one-third the 
length of the shaft from the head ; it is long, Hat and not as prominent as in the 
smaller species of the genus; its position in the Tapir is nearer the middle of the 
shaft. In Rhinoceros we see a wide variation from the above form in the position 
of this trochanter, which is placed at about the middle of the shaft. 
The distal extremity of the femur in this species is iiniisiially heavy and broad, 
very much more so than in that of the Tapir. The trochlear surface is narrow and 
long. The internal ridge of the trochlear is more elongate and i)roniinent than the 
external. Posteriorly the trochlear surface becomes continuous with the condyles, 
the latter being heavy and extending some distance backward. The intercon- 
dylar notch is long and very deep. The tuberosities are prominent ; the surface 
between them and the trochlear is convex instead of concave as in Tapirus. 
The posterior face of the shaft presents a number of differences distin- 
guishing it from that of the Tapir; the lower portion is very broad and flat 
and resembles in this respect the shaft of the femur in the Rhinoceros. In the 
Tapir and in the Equine series the posterior external border of the shaft of the 
femur presents a deep fossa for the flexor perforatus muscle. In Palceosyops this 
fossa is entirely absent, and as in Rhinoceros, the surface for the origin of 
this muscle is flat and slightly rugose, somewhat more so tlian in the latter. 
Patella, No. 10,282. — The patella is narrower and much more elongated 
than in the Tapir. Superiorly it is rounded and shows no projecting processes ; 
the inferior end is pointed. The anterior enlargement of the patella is slightly 
curved outward. Its internal articular surface is long and narrow, with the 
external articular portion broader than the internal. 
Tibia, No. 10,282. — The tibia of this species is more slender and rather longer 
than in Rhinoceros bicornis. The femur on the other hand in Rhinoceros is longer 
than the same bone in P. paludosus. The upper articular surface of the tibia is 
much broader transversely in comparison to the antero-posterior diameter, whereas 
in the Rliinoceros these diameters more nearly approach each other. 
The superior external facet is also long proportionately, the internal fiicet 
being much shorter and rounder. The crest of the tibia is very prominent and 
