Zoology · Ch 4 — Organ and Organ Systems in Animals
Reproductive System
Reproductive System
Earthworms are hermaphrodites (monoecious animals), meaning each individual carries both male and female reproductive organs, yet they still cross-fertilize rather than self-fertilize because the two sets of organs mature at different times - sperm develop before eggs, a pattern called protandry. In the male system, two pairs of testes in segments 10 and 11 produce germ cells that mature into spermatozoa within two pairs of seminal vesicles; two pairs of ciliated seminal funnels connect to long vasa deferentia that run back to open at the male genital aperture in segment 18, which also bears penial setae used during copulation, while a pair of prostate glands nearby cements the sperm into bundles called spermatophores. In the female system, a pair of ovaries in segment 13 releases ova that pass through ovarian funnels into oviducts, which join and open through a single median female genital pore in segment 14; three pairs of spermathecae in segments 7-9 receive and store a mating partner's sperm. During mating, two worms …
What this figure shows. A dissection-style diagram of the anterior segments showing, on the male side, the testis, seminal vesicle, seminal funnel, vas deferens and prostate gland with its duct, and on the female side, the ovary and oviduct, together with the paired spermathecae and the brain/sub-pharyngeal ganglion/peripharyngeal commissure of the nervous syste …