These formed from the branchial arches, in the embryo.

The free edge of the operculum begins to expand, but does not yet cover the branchial arches.

Gill filaments are sprouting on branchial arches one and two.

There is a prominent bulge in the operculum edge below the branchial arches.

In fish, the branchial arches support the gills.

Branchial arches, grooves which will form structures of the face and neck, form.

In one region, neural crest cells develop into five structures - the branchial arches - which grow to form the face.

The opercular flap, which is as wide as the eye, obscures the branchial arches in side view.

Disturbances in the development of the branchial arches in fetal development create lasting and widespread effects.

Since the branchial arches are important developmental features in a growing embryo, disturbances in their development create lasting and widespread effects.

It is a relatively common congenital anomaly of the first branchial arch or second branchial arches.

Branchial arches, or gill arches, are a series of bony "loops" present in fish, which support the gills.

Preauricular sinuses and cysts result from developmental defects of the first and second branchial arches.

The dorsal ends of branchial arches 4 and 5 are attached, but not fused into a "pickaxe" as in lamniform sharks.

Examples of detectable evidence of vestigially metameric structures include branchial arches and cranial nerves.

The facial skeleton, splanchnocranium or viscerocranium consists of a part of the skull that is derived from branchial arches.

Their full set of gill rakers in their branchial arches have never previously been found in an eel, but are common in bony fish.

Neoteny is evident in some larval specimens by the retention of branchial arches and a high degree of ossification in the hyobranchial skeleton.

Unlike skeletal muscles that developmentally come from somites, branchiomeric muscles are developmentally formed from the branchial arches.

At first these bones were thought to be part of the branchial arches which surround the pouch, or remains of prey that had just been eaten before the animal died.

Special visceral efferent (SVE) refers to efferent nerves that provide motor innervations to the muscles of branchial arches.

Note that in fish, the arches continue to develop as branchial arches while in humans, for example, they give rise to a variety of structures within the head and neck.

Other animals that would later be classified as temnospondyls were placed in a group called Ganocephala, characterized by plate-like skull bones, small limbs, fish-like scales, and branchial arches.

Midline cervical clefts are a cutaneous condition, a rare congenital anomaly resulting from incomplete fusion of the branchial arches in the ventral midline of the neck.

Thus, ectomesenchyme plays a critical role in the formation of the hard and soft tissues of the head and neck such as bones, muscles, teeth, and, most important, the branchial arches.