Reproductive System of Earthworm

This note is adapted from Reena Lamsal’s note from NHC.

Earthworms are hermaphrodites animals that mean a body of earthworm consists of both male and female organs.

Reproductive System of Earthworm

Male reproductive System of Earthworm.

Earthworm’s male reproductive system consists of two pairs of the testis, two pairs of spermiducal funnel, two pairs of seminal vesicles, two pairs of vasdefence, one pair of prostatic gland and one pair of the common prosthetic prostatic spermatic duct and one pair of male genital aperture.

Testes

(The singular form is Testis and the plural form is Testes)

Two pairs of testes are found in the intersegmental groove of the 10th and 11th segments. Testes are 8-1- tubular like structure containing sperm mother cell. These cells undergo meiotic division to produce sperms which are in an immature condition called Testisacs.

Testes Sacs

Testes sacs are the thin membranous structure which covers the two pairs of testes and two pair of seminal vesicles which is present in the 11th segment.

Spermatogonia

These spermatogonia are shed into the testes sac and enter into the seminal vesicles.

Seminal Vesicle

Two pairs of the seminal vesicle are found in the 11th and 12th segments on either side below each testis. Seminal vesicles contain nutritious secretion which helps to nourish the sperm.

Spermiduccal Funnel

Two pairs of Spermiduccal Funnel are found just below testis on either side in the same segment (10th and 11th). Spermiduccal Funnel receives matured sperm and passes down to vas deference.

Vas Deference

Two pairs of Vas Differencia arise from each Spermiduccal Funnel which runs downwardly on either side and enters into the prostatic gland in the 18th segment.

Prostate Gland

These are irregular, flat, whitish bodies extending from 16th to 20th segments. Prostatic glands secrete alkaline secretion. It receives vas differencium and the sperm from Spermiduccal Funnel. The total content of the prostatic gland plus spermatic fluid is discharged through a common duct.

Common Prostatic Spermatic Duct

These are one pair of duct arising from the prostatic gland which opens into the male genital aperture in the 18th segment. Through this duct the male gamete along with prostatic secretion discharge out.

Male Genital Aperture

Male Genital Apperture is two openings in the ventral side in the 18th segment. Through these openings, spermatic fluid is discharged.

Female reproductive system of Earthworm.

The female Reproductive System of earthworm consists of one pair of the ovary, one pair of the oviducal funnel, one pair of the oviduct and single female genital aperture and four pair of spermathecae.

Ovary

One pair of the ovary is situated in the intersegmental groove of the 13th segment. Ovaries are fan-like structure made up of 8-10 lobules, arranged column-wise. The base of the ovaries are narrow but the posterior part is expanded. Each lobule contains, ovum producing mother cell at the base which undergoes meiotic division to form the ovum. During development and maturation size of the ovum increases and finally, these ova shed (come) by rupturing the ovarian membrane.

Oviduccal Funnel

These are folded fimbriated, finger-like structure which catches the ova which are shed from respective sides of ovaries. The oviductal funnel has a central opening that opens into the oviduct.

Oviduct

These are tube-like structure with ciliated inner lining. These tubes carry ova from the oviductal funnel to the female genital aperture.

Female genital aperture

It is the single opening situated mid ventrally in the 14th segment. Through these opening ova are discharged into the clitellum.

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