THE CHIMPANZEES AND ORANGS. 17 
the insertion of the ligamentum teres is relatively larger and deeper. The articular car- 
tilage is co-extensive with the head at the upper half of the ball; but it is defined by a 
groove at the lower half from a rough non-articular tract, beyond which the neck begins : 
the ridge defining the rough tract from the neck is most strongly marked below and behind, 
where it forms a curve encroaching upon the head ; the non-articular tract of ihe head is 
broader before than behind, and the head projects from or beyond the neck at this part. 
The neck (fig. 6, c), having its least circumference near the head, expands quickly to join 
the shaft, and much more so vertically than transversely ; so that it is subcompressed, 
with the anterior and posterior surfaces rather oblique from above downward and back- 
ward. The upper part of the neck is continued into the fore part of the great trochanter, 
and forms the pretrochanterian protuberance there ; the lower part curves more rapidly 
down to the shaft than in the Gorilla or Chimpanzee, the base of the neck being more 
extensive, especially vertically, than where it expands to join the head. The trochanter 
presents a rough convex subquadrate surface externally, is very thick and irregular with 
protuberances and hollows anteriorly, thinner with an obtuse curved border behind, and 
concave towards the head ; the upper part, terminating in the apex or upper and hinder 
angle of the trochanter, is bent towards the head, but does not rise so high as that part : 
on the concave side of the base of the trochanter is a large pit. On the outer convexity 
a rising, more or less marked, extends from the upper and hinder angle diagonally to the 
lower and front angle ; to which rising or line the tendon of the meso-gluteus is attached. 
On the smoother surface below the line a bursa is placed, over which the tendon of the 
ecto-gluteus glides to its insertion. The posterior prominent border of the great tro- 
chanter is continued, with a slight subsidence, to the small trochanter (e); which is 
more prominent in proportion to its size than in the Gorilla or Chimpanzee, and 
projects and is placed more inwards. A much lower ridge is continued from the upper 
and fore part of the great trochanter obliquely downward and inward to opposite the 
lower part of the base of the small trochanter, below which it passes in its way backward 
to join the linea aspera. In its whole extent this ridge is called the ‘spiral line,’ and 
to the upper half is sometimes applied the term ‘anterior intertrochanteric line ;’ but 
it does not join the small trochanter. Between this and the head is a nearly parallel 
linear indication of the line of reflexion of the synovial bag: the capsular ligament is 
attached to the anterior intertrochanteric line. 
The shaft, with a full oval transverse section at its upper fourth, gradually decreasing 
in breadth, becomes more convex anteriorly in the transverse direction; and the same 
section, in the middle two-thirds of the shaft, presents a full pyriform shape, the linea 
aspera forming the apex. 
A ridge (ecto-gluteal) beginning below the middle of the base of the great trochanter, 
a rough tract from the small trochanter, and the ‘ linea spiralis ’ converge as they descend 
to form the ‘linea aspera’ (9, g, fig. 6): thisis most prominent along the midde third of 
the shaft, forming there a production of dense osseous matter, which must afford, like a 
VOL. V.—PART I. D 
