The long branchial region has up to 54 pairs of gill pores opening dorsally.

Their tough cuticle and their distinct branchial region with strongly tufted branchiae are characteristic.

They have triangular spines and well-defined gastric and branchial regions internally.

Ebalia tumefacta is a small, roughly diamond-shaped crab, with noticeably bulbous branchial regions.

Its epibranchial region is bulbous, and it bears at least one transverse ridge in the protogastric, hepatic or branchial region.

The lollipop catshark is so named because of its peculiar tadpole-like shape, with an enormously expanded head and branchial region (containing the gills) coupled with a slender, cylindrical body tapering towards the tail.

On the basis of experimental and clinical evidence, the hindbrain and branchial region of the head are particularly sensitive to the effects of retinoic acid but the phenotypes are complex and hard to interpret, and how and if they relate to Hox expression has not been clear.

It is important to note that segmentation in the hindbrain has a role outside the neural epithelium in patterning the branchial region by way of the neural crest, and the experimental and clinical dysmorphologies induced by retinoic acid frequently include the appearance of structural alterations in the first branchial arch.