176 GEO. S. HUNTINGTON 
new element thus added to the bronchial tree of the right lung, 
is the Eparterial Bronchus (fig. 15, Hp.). It arises from the 
dorso-lateral aspect of the stembronchus cranial to the origin 
of V! and nearer to the tracheal bifurcation. It lies behind 
rather than above the main right pulmonary artery, which vessel 
descends caudo-laterad over its ventral surface to dip dorsad 
between it and V! and then continue its descent dorsal to the 
remaining ventro-lateral primary branches of the stembronchus. 
It might hence be defined more correctly as the Katarterial 
Bronchus, but all arterial relations are of very secondary mor- 
phological significance in the analysis of bronchial organization. 
Aeby named it the Eparterial Bronchus, and this designation 
should stand for all time on the basis of historical priority, no 
matter if in individual mammalian forms the bronchus starts 
behind, above, or to the inner side of the artery. These are 
secondary and unimportant details. The cardinal fact remains 
that Aeby was the first to recognize the existence of the bronchus 
and its morphological significance in the intrapulmonary archi- 
tecture. That fact out-balances any baptismal slips its god- 
father may have committed. Besides there are numerous mam- 
malian types in which the designation is quite pertinent. It is 
concise, thoroughly incorporated in the anatomical literature, 
and no observer would be misled for a moment by its use in cor- 
rectly diagnosing any given bronchial tree. Surface indications 
pointing to a newly acquired independence and greater freedom 
of the cranial segment of the preceding primitive ‘upper lobe’ 
are not wanting in many forms. The district of the new epar- 
terial bronchus becomes separated from that of the first ventral 
hyparterial bronchus by a correlated new fissure, the secondary 
interlobar incisure. The former now constitutes the definitive 
‘upper lobe’ proper, the latter forms the ‘middle lobe,’ confined 
to the ventral pulmonary region (fig. 15, MW). Both are sepa- 
rated from the remainder of the archeal lung-stem, the ‘lower 
lobe,’ by the older main interlobar incisure. 
On the left side conditions remain much as they were before 
the inauguration of the right eparterial development (fig. 13). 
There is ordinarily no left eparterial neomorph bronchus. ‘The 
