[1] M. divisor is a free-living, ectocommensal parasite of various comatulid feather stars, including Promachocrinus kerguelensis and Notocrinus mortenseni, and shows little host specificity.

It is disk-shaped, surrounded by nine pairs of marginal cirri of equal sizes, and an unarmed proboscis at the oral end.

The underside bears five evenly-spaced pairs of parapodia around two-thirds of the way to the outside of the disk, with long and slender parapodial hooks.

The next stage, described from a specimen 310 μm in length, shows blunt rudiments of marginal cirri, with the last, thicker pair destined to become the caudal processes.

The caudal processes thicken before elongating past the length of the marginal cirri, while the proboscis gains the ability to retract, giving the myzostomid its adult appearance.