ray number
true
uberon
ray_number
x ray_number N if and only if (i) x is a ray, and (ii) x is ancestrally associated with ray number N in a series of phalanges repeated along a radio-ulnar or equivalent axis, with ray_number 1 being the anteriormost ray.
UBPROP:0000104
ray_number
The correct terminology is yet to be established; in tetrapods 'ray' might mean the mereological sum of the phalanges of a manual digit plus a metatarsal bone (or equivalent for hindlimb)