monactinal, a.
(mɒˈnæktɪnəl)
[Formed as next + -al1.]
Of a sponge-spicule: That has only one ray.
| 1887 S. O. Ridley in Rep. Voy. Challenger XX. Introd. 6 The chief spicules of the group are ‘monactinal’, that is to say, consisting of only a single ray. |