Phylum Nemertea (Rhynchocoela)

Nemertean Taxonomy
Nemerteans are classified according to the relation of the nervous system to the
musculature, and the structure of the proboscis.
Class Anopla - ‘Unarmed’ Gr.
These animals are characterized by a mouth lying posterior to the brain, a CNS located
directly below the epidermis, and a proboscis that bears no stylets but instead works as
a wrap-around lasso. 2 Orders: Palaeonemertea, Heteronemertea
E.g. Baseodiscus
Class Enopla - ‘Armed’ Gr.
The enoplans have a mouth that lies anterior to the brain. The CNS is located within
the muscular layer, and the proboscis is armed in some species. Where an armed
proboscis does occur, a poison sac lies directly below the stylet, and poison is ejected
into wounds created by the stylet. 2 Orders: Hoplonemertea, Bdellonemertea
Ex. Prostoma - a fresh water armed nemertean. Geonemertes - a tropical terrestrial
genus of armed nemertean, which lives under rocks and stones.
Pelagic nemertean