Hermaphrodites bear testis and ovary within the same organism, (e.g., earthworm or Pheretima).

Direct development occurs in organisms in which there is no larval stage in the life-cycle and therefore no metamorphosis takes place, (e.g., Pheretima and Lumbricus).
Chemoreceptors or chemosensors are the sensory receptors used in sensing chemical substances.(e.g., olfactory receptor and taste buds in mammals).
Blood glands in earthworm are specialised glands that are associated with the generation of blood cells and haemoglobin in Pheretima.