one of a series of rudimentary depressions on the surface of the embryo between adjacent branchial arches, homologous to the branchial clefts of gill-breathing ancestral forms.
one of a series of rudimentary outcroppings of the inner pharyngeal wall, corresponding to the branchial grooves on the surface.
shaped like a gill. Historical Examples An Introduction to Entomology: Vol. IV (of 4) William Kirby