Source : Webster's Revised Unabridged Dictionary (1913)

Procoelian \Pro*c[oe]"li*an\, a. [See {Proc[oe]le}.] (Anat &
   Zo["o]l.)
   Concave in front; as, proc[oe]lian vertebr[ae], which have
   the anterior end of the centra concave and the posterior
   convex.

Procoelian \Pro*c[oe]"li*an\, n. (Zo["o]l.)
   A reptile having proc[oe]lian vertebr[ae]; one of the
   Proc[oe]lia.