Page 359. 
98 NOTES ON AN OSTRICH LATELY LIVING 
2 feet long and arranged like a spirally twisted cone, were situated 
11 feet from the pylorus, which is very different from their situation 
in most birds, as has been noticed by Owen. 
The diaphragm was well marked. It formed a partition which 
divided the thoracic cavity into two parts, one posterior and small 
containing the lungs, and the other anterior and large containing the 
heart and liver. It was a fibrous membrane, concave forwards, with 
a muscular attachment at either side to the ribs and intercostal 
tissues, which it joined in about the middle of their course. This 
muscular part was formed of transverse fibres in the middle and upper 
part of the chest, while the lower ones slanted slightly upwards as 
they coursed towards the median line. They were about 2 inches 
long, and formed a thin layer. The pleural cavity was closed above 
and below by the fibrous diaphragm becoming blended with the first 
and last ribs. 
The anterior thoracic cavity, which contained the pericardium- 
coated heart in its upper part, entirely independent of the pleural 
cavity, was divided into two by a dense fibrous membrane which 
sprang from two vertebral crura, much as the human diaphragm, 
and extended above the line to join the sternum, along the border 
which articulated with the ribs, leaving the heart entirely in front of 
it; its concavity was directed downwards and forwards; and: it was 
separated from the diaphragm proper by very large air-cells. The 
cesophagus also ran in the interval; but the aorta was included in 
the pleural cavity, being clearly seen through the membrane of the 
diaphragm, along the median line, before its removal. 
The liver was completely separated from the abdominal cavity by 
a fibrous membrane, so that when the included viscera had been re- 
moved it was not at all brought into view. The mesentery was very 
dense and strong, the vessels, especially the veins, being of large 
size. : 
Some further points in the anatomy of this bird are not without 
interest. 
There are three parietal abdominal muscles as usual, the muscular 
fibres of the external and internal being nearly parallel and transverse, 
while those of the intermediate one are longitudinal. They each send 
down a dense fascial attachment to the pubic bone; and a semilunar 
free margin between the ilium and the superior pubic crest appears 
closely allied to Poupart’s ligament, the anterior crural vessels and 
nerves going underneath it to enter the leg. It may be here men- 
tioned that the main vein of the thigh is the internal saphenous; but 
the main artery is the one that goes through the sciatic notch, there- 
fore the sciatic. These come into relation with one another in the 
loop for the biceps tendon at the knee, 
