Specimen hardened _in situ_. Space between heart and lungs was
occupied by pericardium and fat.
]
The interlobar fissures begin at the ventral margin of the lung and
pass toward the root. Those of the left lung lie opposite to the
fourth and sixth ribs. The diaphragmatic lobe is the largest, and has
the form of a three-sided pyramid with its base resting on the
diaphragm. The cardiac lobe is prismatic and forms the posterior
margin of the cardiac notch; its long axis corresponds to the fifth
rib. The apical lobe of the left lung is small and pointed; its
ventral margin lies on the pulmonary artery and the anterior aorta;
below this the space in front of the heart is occupied by the apical
lobe of the right lung. The cardiac lobe of the right lung is much
larger than that of the left lung, and covers the right face of the
pericardium, so that the latter has no contact with the lateral wall
of the thorax.
The =lobulation= is very distinct on account of the extremely large
amount of interlobular tissue.
In the =sheep= the costal attachment of the diaphragm resembles that of
the horse, and the basal part of the lung corresponds thereto. The
lobation of the lungs resembles that of the ox, but the lobulation is
very indistinct. The pleural sacs extend under the first lumbar
vertebra.