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Earthworms and their kin, in the subclass Oligochaeta, lack eyes but have photoreceptor cells in the skin, especially in the dorsal portion of the anterior end. They also lack parapodia and appendages on the prostomium, the body and the periproct (terminal segment on which the anus is located).
Earthworm mating occurs on the surface, most often at night. Earthworms are hermaphrodites; that is, they have both male and female sexual organs. The sexual organs are located in segments 9 to 15. Earthworms have one or two pairs of testes contained within sacs.
Nearly all polychaetes have parapodia that function as limbs, while other major annelid groups lack them. Parapodia are unjointed paired extensions of the body wall, and their muscles are derived from the circular muscles of the body. They are often supported internally by one or more large, thick chetae.
Pheretima is a genus of earthworms found mostly in New Guinea and parts of Southeast Asia. Species belonging to the genus Pheretima have a clitellum, which is a band of glandular tissue present on segments 14 to 16. Individuals are hermaphroditic and reproduction can be either sexual or parthenogenetic. Female genital pores lie on the ventral ...
Microscope photograph of a parapodium from a specimen of Arctonoe sp. showing the internal acicula that support the two lobes of the parapodium. This parapodium is from a Museums Victoria specimen. Most species of polychaete annelids have paired, fleshy parapodia which are segmentally arranged along the body axis. Parapodia vary greatly in size ...
C, Okefenokee Swamp, GA (Pfl-2). Single star, male gonopore; double star, female gonopore, three annuli posterior to male. Scale bars, 1.0 mm. In earthworms, the clitellum can only be seen when the worm is sexually mature. It may be white, orange-red or reddish-brown in colour. Earthworms are ready to mate when their clitellum is orange. [2]
However, 'earthworm' can be a source of confusion since, in most of the world, other species are more typical. For example, through much of the unirrigated temperate areas of the world, the "common earthworm" is actually Aporrectodea (=Allolobophora) trapezoides, which in those areas is a similar size and dark colour to L. terrestris.
As with other earthworm species, E. fetida is hermaphroditic, and uniparental reproduction is possible, even if usually the reproduction is between copulating individuals. [16] The two worms join clitella , the large, lighter-colored bands which contain the worms' reproductive organs, and which are only prominent during the reproduction process.