and referred to as the "coracoid minor."

Bhaduri and Biswas (1954:348) have suggested that "the accessory
sternoclavicular artery occurring sporadically as it does in some
species of diverse groups may not have any phylogenetic value."

In no case did I find more than one coracoid artery on a side. When one
of the highly variable arteries feeding _Mm. coracobrachialis posterior_
and _sternocoracoideus_ (arteries 4 and 4a, Fig. 7) arises from the
subclavian or axillary artery instead of from the coracoid artery, that
vessel may have been interpreted by others as a second (accessory or
minor) coracoid artery. If so, this artery probably does not "occur
sporadically." Rather, its origin from the subclavian, axillary, or
thoracic artery may be sporadic, subject to individual variation, and it
may have been overlooked when it arose from the coracoid artery.

Of the vessels described here, the only one that differed distinctly in
one species was the sternal artery. In _Scardafella inca_ the right
sternal vessel was long, extending down the mid-line of the inner
surface of the sternum, whereas in other columbids the right and left
arteries ramified on the anterior part of the inner surface of the
sternum, or were altogether lacking. I am unable to account for the
differential development of this artery in _S. inca_.

In describing the arterial arrangement in the seven species of Indian
columbids named earlier, Bhaduri and Biswas (1954:348) state that all
species except _Treron phoenicoptera_ have two "internal mammary"
arteries on each side "showing variable sites of origin." These arteries
were later described (Bhaduri, Biswas, and Das, 1957:4-5) as "a slender
(_outer_) _internal mammary_ artery... to the outer wall of the thoracic
cavity" and "a slender (_inner_) _internal mammary_ artery... to supply
the inner wall of the chest cavity." From this description, the question
arises as to whether the "outer" one of these arteries should properly
be called an _external_ instead of _internal_ mammary artery. In any
case, I saw no specimen possessing two thoracic arteries on a side.

Interfamilial Differences

As shown above, there is a high degree of individual variation in the
vessels being considered, while at the same time, few interspecific
differences were noted within the families. On the other hand, the
vascular arrangement of swallows consistently differed from that of
pigeons in the species studied. The differen