It is usual for the umbrella to have an even, circular, uninterrupted margin; but in the order Narcomedusae secondary down-growths between the tentacles produce a lobed, indented margin to the umbrella.
Leaves 3 to 5 lobed, often large.
Leaves 3 to 5, seldom lobed.
Leaves 3 to 7 lobed.
Nearly allied is Neophocaena phocaenoides, a small species from the Indian Ocean and Japan, with teeth of the same form as those of the porpoise, but fewer in number (eighteen to twenty on each side), of larger size, and more distinctly notched or lobed on the free edge.