584 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 
other. Fibres less distinctly pronounced also pass from the articulating processes to 
the sides of the spines. 
Hip-joint.—The head of the femur is set almost horizontally at a right angle to the 
acetabulum, whereas the axis of the shaft of the bone assumes a perpendicular right 
angle to that of the pelvis; hence it follows that while the femur has considerable 
power of rotation, its chief movement is somewhat after the manner of a pendulum on 
the side of the pelvis. An extra ligament, presently to be spoken of, restrains the 
motion forwards, while the peculiar attachment of the muscles also limits free action 
in other respects. 
The capsular ligament (¢) is of considerable strength all round, but more lax infe- 
riorly. Upon the upper or dorsal surface it is very much strengthened by a thick, 
aponeurotic, triangular-shaped portion, which arises broadly from the dorsal curved 
margin of the cotyloid cavity, and, running directly outwards, narrows as it is inserted 
into the anterior inner and upper surface of the great trochanter. Partly united with 
the above, but yet to some extent sufficiently distinct, is an elongated slip with a 
posterior concave border, which comes from the ischium just behind the other, and 
slants forwards and outwards upon the posterior surface of the great trochanter. This 
latter band (is.f.) is evidently the homologue of Macalister’s ischio-femoral accessory 
ligament, described by him as of occasional occurrence in Man’. 
These accessory ligaments form, so to speak, a firm unyielding roof to the head of 
the femur, so that all chance of dislocation upwards is prevented. The hinder one, 
when on the stretch, checks or counteracts the force of the multiple short adductors. 
There is no distinct ilio-femoral ligament, the capsular fibres being of nearly uniform 
thickness where the ilio-femoral accessory band ought to be found. ‘The short adductor 
muscles may supply this want. 
No ligamentum teres exists—the head of the bone being covered by a moderately 
thick, smooth layer of cartilage. A considerable-sized synovial sac fills the triangular- 
shaped depression at the bottom of the acetabulum, and passes underneath the trans- 
verse ligament; this sac supplies the lubricating media of the joint. 
The fibro-cartilage constituting the cotyloid ligament is thickest at the upper or 
dorsal margin of the acetabulum. That portion of it termed the transverse ligament is 
a strong, narrow, tendinous-like band bridging the oval notch. 
Knee-joint.—The so-called ligamentum patelle (/.p, fig. 35), or union between the 
lower border of the patella and the tibia, is very strong. Within the joint there is a 
fatty cushion adherent to it, which acts as a soft elastic buffer or pads the roomy joint. 
The internal lateral ligament (¢./, fig. 37) and external lateral are fully developed. 
The semilunar fibro-cartilages correspond in contour to the shape of the articulating 
surface of the tibia. They resemble those of Man inasmuch as the outer is more 
' «Notes of Two Undeseribed Ligaments of the Human Body,” Proc. Roy. Irish Acad. (read 25rd April, 
1866), vol. ix. pl. iv. fig. 2. 
