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Which invertebrates produce both sperm and eggs in the same individual?

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Diagram comparing reproductive pathways: arrows show sexual reproduction forming a diploid zygote from oocyte and sperm, haploid parthenogenesis forming a haploid individual, and two types of diploid parthenogenesis-automixis and apomixis-both resulting in diploid individuals. Symbols indicate haploid and diploid stages. — Animal reproductive system The process of sexual reproduction and several forms of parthenogenesis.

Invertebrates that produce both sperm and eggs in the same individual are known as hermaphrodites (or monoecious). This condition is found across several invertebrate groups:

Annelids: All oligochaetes, such as the earthworm, are hermaphroditic, possessing both male and female reproductive organs. Leeches are also monoecious.12
Mollusks: Many gastropods, particularly among opisthobranchs and pulmonates, are hermaphrodites. Some species utilize an ovotestis, a structure that produces both sperm and eggs.13
Arthropods: While most arthropods are dioecious (having separate sexes), barnacles are a notable exception and are hermaphroditic.45
Urochordates: Most urochordates (such as sea squirts) are hermaphroditic, often with one ovary and one testis lying side by side.6

It is important to note that while these animals possess both sets of organs, many have evolved mechanisms to favor cross-fertilization with other individuals rather than self-fertilization.142