Adjective
ray-finned (not comparable)
(of fish) In the Actinopterygii taxonomic class of fish, all having in common lepidotrichia (a kind of fin made of webs of skin supported by bony or horny spines).
The group Osteichthyes is divided into the ray-finned fish ( Actinopterygii ) and lobe-finned fish ( Sarcopterygii ). Source: Internet
The largest subclass, the Actinopterygii (ray-finned fish) are monophyletic, but with the inclusion of the smaller sub-class Sarcopterygii, Osteichthyes is paraphyletic. Source: Internet
In ray-finned fishes (by far the largest group), the optic tectum has a layer—the marginal layer—that is cerebellum-like. Source: Internet