were examined with a dissecting microscope to enumerate and identify the developmental stage of all enclosed metacercariae.
Some attention to the structure of the original connection between the brain case and the gill arches
is useful in understanding the basic changes in pressure that allowed for the eventual modification of the jaw and ear.
We removed gill arches
from six kokanee salmon infested with gill lice and preserved them in 70% ethanol for identification of the species of gill lice.
i) tooth-like structures were found on gill arches
in a primitive jawless vertebrate, indicating that teeth evolved prior to jaws.
In this case, shared developmental mechanisms pattern the skeletons of vertebrate gill arches
and paired fins," he added.
Anterior three gill arches
each of hypobranchial, ceratobranchial, epibranchial and pharyngobranchial, fourth arch of ceratobranchial and epibranchial, fifth arch comprising single ceratobranchial.