Ascaris reproduces sexually and is dioecious. It shows sexual dimorphism.
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(1) Male reproductive organs:
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These organs are confined to the posterior half of pseudocoel and include following organs.
1. Testis:
Male ascaris is monarchic, possessing a single testis which is long, thin and highly twisted tube like structure.
It occupies most of the pseudocoel in posterior 2/3 of the body. Wall of testis is made up of a single layer of cuboidai cells.
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Proximally it is closed and contains germinal zone that produces spermatogonia through budding from a single germinal cell.
The rest of the testis contains a solid axis called cytoplasmic rachis. It serves as a surface of maturation and growth of the sperms.
2. Vas deferens:
Distally testis leads into short and thick twisted tubes, the vas deferens. It is distinguished from testis in having a lumen in place of the rachis.
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3. Seminal vesicle:
Vas deferentia are followed by a much thicker, wider, somewhat muscular straight tube, the seminal vesicle. It serves to store mature sperms.
4. Ejaculatory duct:
Terminal part of seminal vesicle narrows to form a highly muscular ejaculatory duct. It joins rectum to form the cloaca. Its wall contains a number of prostatic glands, whose secretion helps in copulation.
5. Penial setae:
Two small contractile penial sacs open dorsally into the cloaca. Each sac contains a small needle like penial orcopulatory seta made up of cuticle.
The spicules protruded and retracted through the cloacal aperture by the action of protractor and retractor muscles of the sac wall spicules help in opening the female gonopore for copulation.
(2) Female reproductive system :
This system is situated in the posterior 2/3 part of the body and consists of ovaries, oviduct, uteri and vagina.
1. Ovaries:
Female Ascaris is didelphic i.e., it has two ovaries two oviducts and two uterus. Each ovary is a long, thin thread-like much twisted tube.
These are also telogenic like the testis. Proximally it bears germinal cell to produce ova. Remaining distal part of the ovary contains cytoplasmic rachis and acts as growth zone for ovum maturation. There is no lumen.
2. Oviduct:
Each ovary leads into a long coiled oviduct of same thickness and similar wall without any external distinction. It has a lumen.
3. Uteri:
Each oviduct followed by a thick and long but straight uterus extending from behind forwards, its wall is thick and formed of an inner layer of tufted secretory cells surrounded by a muscular layer. Uteri serve to store the eggs after fertilization.
4. Vagina:
Anteriorly both uteri bend median wards and join together to form a very short and relatively narrow vagina. Its wall is quite muscular and contractile. Anteriorly it opens out by the midventral transverse slit-like female gonopore or vulva.