PHYSIOLOGY, AND PATHOLOGY OF THE CHIMPANZEE. 353 



digitations fuse with the pectoralis major, and the outei' ones 

 are only covered by the latissimus dorsi. All interdigitate with 

 the serratus magnus. The lateral fibres descend to the anterior 

 superior iliac spine and outer third of Poupart's ligament. The 

 other fibres end in the aponeurosis which is attached to the 

 sternum, the last chondro-sternal junction, the pubis, and the 

 inner two-thirds of Poupart's ligament. The aponeurotic fibres 

 of the two sides cross the mid line into one another. Gratiolet 

 (11) described the aponeurosis in detail, recording the characters 

 of Poupart's ligament, the slight Gimbernat's ligament, the lax 

 adhesion to the deep fascia of the thigh, and the formation of the 

 pillars of the external abdominal ring. The aponeurosis fuses 

 with the internal oblique mesial to the splitting of the apo- 

 neurosis of the latter. And the crural fascia and Poupart's 

 ligament fuse with the aponeurotic origin of the sartorius. 



The internal oblique rises from the outer half of the anterior 

 border of the iliac crest, the anterior superior iliac spine, the 

 outer third of Poupart's ligament, and the lower borders of costal 

 cartilages 10-13. The aponeurosis, which receives the fibres, 

 has a curved line of splitting and runs from the tenth costal 

 cartilage to the inner end of Poupart's ligament. 



The transversalis abdominis arises from the deep surfaces of 

 ribs 10-13, the lumbar fascia, the anterior quarter of the inner 

 lip of the iliac crest, the inner surface of the anterior superior 

 iliac spine, and the outer third of Poupart's ligament. The 

 aponeurosis is attached to the xiphoid and pubis. 



The sheath of the rectus is as in Man, and the semilunar fold of 

 Douglas is present. The rectus has two origins, as in Man, but 

 has four inscriptions running right through it to the sheath 

 Pyraniidalis is absent. 



The diaphragm has a comparatively small central tendon 

 receiving muscles arising from ribs 7-13 and interdigitatingwith 

 the transversalis abdominis, from the back of the sternum by two 

 slips, and from the lumbar vertebrae by the crura and extra 

 slips. The right crus arises as low down as the second lumbar 

 vertebra, and the left one from the first. A slip arises from the 

 transverse process of the second lumbar vertebra and one from 

 the side of the body of the first. The lumbo-costal arches are 

 as in Man. 



The quadratus lumborum is related to the lumbar fascia as in 

 Man. It arises from the posterior two-thirds of the inner lip of 

 the iliac crest, where it is continuous with the iliacus, and from 

 all the lumbar transvei^se processes. It is inserted into the inner 

 four-fifths of the last rib and the bodies of the last two dorsal 

 vertebrae. 



Muscles of the Pelvic Extremity. 

 The 2^>soas parvus arises by fleshy fibres from the last dorsal 

 and first lumbar vertebrae, and it is connected by a fascial sheet 

 over the psoas magnus to the remaining lumbar transverse 



