● `color{Brown}"Members"`: They are commonly called `color{Violet}"Annelids"` (from Latin, `color{Violet}"annulus"`: little ring) because of their segmented body.

● `color{Brown}"Habitat"`: They may be aquatic (marine and fresh water) or terrestrial; free-living, and sometimes parasitic.

● `color{Brown}"Basic Features"`: They exhibit `color{Violet}"organ-system level"` of body organisation and `color{Violet}"bilateral symmetry"`. They are `color{Violet}"triploblastic"` and `color{Violet}"coelomate"` animals.

● `color{Brown}"Examples"`: 𝘕𝘦𝘳𝘦𝘪𝘴, 𝘗𝘩𝘦𝘳𝘦𝘵𝘪𝘮𝘢 (Earthworm) and 𝘏𝘪𝘳𝘶𝘥𝘪𝘯𝘢𝘳𝘪𝘢 (Blood sucking leech).

● `color{Brown}"Segmentation"`: Their body surface is distinctly marked out into segments or `color{Violet}"metameres"`, hence they are called `color{Violet}"metamerically segmentated"`.



● `color{Brown}"Locomotion"`: They possess `color{Violet}"longitudinal and circular muscles"` which help in locomotion. Aquatic annelids like `color{Violet}"𝘕𝘦𝘳𝘦𝘪𝘴"` possess lateral appendages, `color{Violet}"parapodia"`, which help in swimming.



● `color{Brown}"Excretory System"`: `color{Violet}"Nephridia"` (sing. nephridium) help in osmoregulation and excretion.



● `color{Brown}"Circulatory System"`: A `color{Violet}"closed"` circulatory system is present.

● `color{Brown}"Neural System"`: Neural system consists of `color{Violet}"paired ganglia"` (sing. ganglion) connected by lateral nerves to a double ventral nerve cord.

● 𝘕𝘦𝘳𝘦𝘪𝘴 an aquatic form, is `color{Violet}"dioecious"`(separate sexes), but earthworms and leeches are `color{Violet}"monoecious"` (same sex).

● Reproduction is sexual.