What's the difference between hexameter and hexametrist?

Hexameter

Definition:

(n.) A verse of six feet, the first four of which may be either dactyls or spondees, the fifth must regularly be a dactyl, and the sixth always a spondee. In this species of verse are composed the Iliad of Homer and the Aeneid of Virgil. In English hexameters accent takes the place of quantity.
(a.) Having six metrical feet, especially dactyls and spondees.

Example Sentences:

(1) Two possible structures are suggested that are compatible with the experimental data: (a) a hexosaminidase B like structure with higher extent of glycosylation; (b) a hexameter of beta chain, possibly arranged as three beta2 subunits.
(2) Though Lord Derby's version is in unrhymed iambic pentameters, rather than the dactylic hexameters of the original, the narrative retains the density of an exciting though tragic war novel, never matched for scenes of ferocity and courage and the maintenance of honour, with its graphic descriptions of ghastly wounds, nearly all of which result in death.