Heteronemertea is a monophyletic order of about 500 species of nemertean worm. It contains genera such as Lineus and Cerebratulus, and includes the largest and most muscular nemerteans.

Almost all heteronemerteans have three primary body-wall muscle strata: an outer longitudinal, a middle circular, and an inner longitudinal. The lateral nerve cords are outside the circular muscle, as in palaeonemerteans, but separated from the epidermis by the usually well-developed outer longitudinal muscle.

Heteronemertea. Retrieved January, 01 2022, from en.wikipedia.org/wiki/Heteronemertea.

Lineidae is a family of nemertean worms. It contains the following genera:

Lineidae. Retrieved January, 01 2022, from en.wikipedia.org/wiki/Lineidae.