178 



process, only, of the third sacral vertebra. Posteriorly, the narrow 

 rod-like portion of the ilium widens towards the acetabulum. 

 The pubic elements come together at a wide symphysis, and are 

 completely ankylosed. The posterior edge of the pubic and 

 the ischial portion of the pelvis diverge as they ascend, and the latter 

 fuses with the metapophyses and transverse processes of the two 

 last sacral vertebrae. The posterior outlet of the pelvis has a 

 markedly triangular outline (fig. 4). The acetabulum is circular 

 and deep, and has a w^ide cotyloid notch posteriorly ; it is imper- 

 forate, but its internal wall is very thin. A round ligament exists. 

 The obturator foramen, nearly circular, is situated below and 

 behind the acetabulum, and is about one-third of its diameter. 



MARSUPIAL BONES. 



These are two very small osseous nodules, slightly divergent 

 anteriorly, which lie in the tendon of the external oblique muscles 

 of the abdomen, close to their attachment to the anterior border 

 of the pubic sympliysis. They are scarcely visible without a lens, 

 and are consequently liable to over-looked. 



THE THIGH AND LEG. 



(PI. YIIL, tigs. 6 and 7.) 



In the femur (fig. 6), the head is approximately spherical, but 

 tapers somewhat to a blunt conical point ; ib is marked by a small 

 depression for the round ligament. The neck is short and con- 

 stricted, standing out almost at right angles to the shaft, and there 

 is a small but conspicuous tubercle at the junction of the front 

 border of the neck with the shaft. 



The great trochanter is much compressed antero-posteriorly, and 

 very broad from above downwards. The lesser trochanter is a 

 small conical process pointing inwards and backwards, situated 

 at the junction of the inferior and posterior border of the neck 

 with the shaft (fig. 6 l.t). The latter is somewhat flattened from 

 before backwards, and widens into an inferior extremity, which 

 presents two condyles, separated in the posterior half of the 

 articular surface by a deep and narrow notch. Besides articulating 

 with the tibia a large portion of this articular surface, by its 

 superior and front part, articulates with the large patella and the 

 external condyle, on its outer side, also articulates directly with 

 the fibula by a surface which is continuous with that for the 

 tibia and patella. 



The shaft of the tibia (fig. 7) is very broad, and expanded in an 

 antero-posterior direction in the upper half, this being due to the 

 projection forwards of the anterior border as a prominent ridge. 

 The bone narrows gradually to the junction of the middle and 

 inferior third where it becomes subtriangular in section. The 



