In the teleosts and elasmobranchs, the individual
gill arches are supported by vertical elements
of the cartilaginous branchial skeleton, which run
through the medial portion of each arch and are
partially calcified in the teleosts. In the elasmobranchs,
the interbranchial septum is supported
by skeletal branchial rays, which extend from the
main skeletal support in each arch. In the teleosts,
these branchial rays are present in the filaments
and in conjunction with abductor muscles are
important in the positioning of the filament in the
water flow (see Hughes, ’84).