actinal
English edit
Etymology edit
From Ancient Greek ἀκτίς, ἀκτῖν- (aktís, aktîn-, “ray”) + -al. The usage was coined by Louis Agassiz (See quotations below.).
Adjective edit
actinal
- (zoology) Pertaining to the side or surface around the mouth in an animal that has radial symmetry such as a starfish.
- 1857, Professor Louis Agassiz, Natural History of North America, Vol. IV, page 376:
- The so-called mouth is always placed at one of these poles, and from it radiate the most prominent organs, in consequence of which I have called this side of the body the oral or actinal area ...
- (zoology) Pertaining to the axis of rotational symmetry in radiate animals.
- 1861, John Timbs, Charles W. Vincent, James Mason, The Year-book of Facts in Science and Art, Simpkin, Marshall, and Co., page 214:
- [Professor Agassiz] gives the names of two axes of the animals; that around which the motion of the animal occurs is the actinal axis ...