"an opening leading from the pharynx to the exterior in aquatic vertebrates and lancelets. In lancelets they function in filter feeding. In fish they contain the gills and are usually in the form of a series of long slits. They are absent in adult tetrapod vertebrates (except for some amphibians) but their presence in some form in the embryos of all vertebrates is a characteristic of the phylum Chordata" (263.
One of the paired openings from the pharynx to the outside, located just in front of the forelimbs.
the opening at the posterior end of the operculum allowing water to flow out of the mouth, past the gills, for breathing.
one of a series of slit openings in the pharynxes of fishes and aquatic amphibians through which water passes
slits on the side of their head - When a shark opens its mouth, water goes in through their mouth and out through the gill slits
A slitlike or porelike opening connecting the pharynx of a chordate with the outside of the body. Gill slits may contain the gills and be used for gas exchange, as in most fish, but may also be used for filter-feeding, or may be highly modified in land-dwelling vertebrates.
Gill slits are gills with individual openings rather than an outer cover. Cartilaginous fish such as sharks, rays, sawfish and guitarfish all have gill slits. Most have five pairs, but a few species have 6 or 7 pairs.
