A type of board that has four inline wheels and four in the back(two on each side) and is deeply concave in the front.

The deeply concave dorsal margin of the opercle also serves to distinguish this genus.

Pieces had been inlet into the substance of the Tree when the original steps wore deeply concave.

The horn shark's supraorbital ridges are low and terminate abruptly; the space between them on top of the head is deeply concave.

It is distinguished from the scalloped bonnethead by its shorter snout, broadly arched mouth, and deeply concave anal fin.

The internal surface is deeply concave and divided into four fossæ by a cruciate eminence.

The loreal region is deeply concave, with the pit entering the eye.

The forewing inner margin is deeply concave before the tornus.

The anal fin originates under the last dorsal ray, and is deeply concave in outline.

The similar scoophead (Sphyrna media) can be distinguished by a shorter snout, broader mouth, and a deeply concave anal fin margin.