Zoology. Situated between neural spines or arches. Cf. interhaemal, adj. a.

Zoology. Of or relating to bony or cartilaginous elements in a fish's fin, distal to the basal segment and supporting a fin ray. Cf. sense B. 4.

Of or relating to a pinnule or pinnules (pinnule, n. 2).

having the spines of the dorsal and anal fins symmetrical; opposed to heteracanth.

Running forwards; continuing or tapering forward at the base; spec. (in bony fishes) designating or relating to the slender, unbranched…