actinost

From New Latin, from Ancient Greek ἀκτίς (aktís, “ray”) + ὀστέον (ostéon, “bone”).

actinost (plural actinosts)

1. (ichthyology) A bone at the base of a paired fin (of a fish)
   • 1889, Dr. G. Baur, “On the morphology of ribs and the fate of the actinosts of the median fin in fishes”, in Journal of morphology‎, volume 3:

     The second well-developed actinost is below the vertebra supporting the subcaudal blood-vessels, but that is not so strong proximally as the first; the ribs are not directed downwards, but backwards, and are entirely separated from each other.

• Scottian, oscitant, tactions