Earthworm Reproductive System Short Notes | Free Biology Notes

Earthworm Reproductive System Short Notes

In this article we will discuss about the earthworm reproductive system

Earthworm Reproductive System

  • Earthworms are hermaphrodites
  • They cannot fertilize their own eggs because of their relative position of male and female genital aperture and they are protrandous
  • Thus, cross fertilization occurs in earthworm.
  • Earthworm reproductive system comprises of male reproductive organs and female reproductive organs

Male Earthworm Reproductive System


  • Two pairs of testes located in 10th and 11th segment
  • Testis produce spermatogonia and each testis is located testis sac
  • Function: They produce sperm

Seminal vesicles

  • It has two pairs of seminal vesicles. They are located in 11th and 12th segments
  • They are also termed as septal pouches, as they develop as septal outgrowths.
  • Function: Maturation of sperm takes place in seminal vesicles

Spermiductal Funnels

  • Earthworms have two pairs of seminal funnels
  • These are located at the 10th and 11th segments.
  • Function: Passing on spermatozoa to the Vasa deferentia and onwards.

Vasa deferentia

  • It is thin, long, narrow, thread like tubular structure
  • Two pairs and each pair is located on the either side of the alimentary canal
  • They extends from 12th to 18th segment.
  • In 18th segment they join together with a thick prostatic duct and forms common prostatic duct
  • Function: They collect sperm from spermatic funnel and give to prostate gland

Prostate gland

  • Pairs of large, solid, and irregularly shaped glandular masses
  • Situated in the segments from 17th to 20th
  • Ventral side of 18th segment, prostatic duct opens via a male genital pore
  • Function: It produce prostatic fluid which is alkaline in nature. It activates sperms. And also it keeps sperm motile.

Accessory glands

  • These are two pair of whitish, spherical structures found one pair in each of the 17th and 19thsegment.
  • Function: Secretion of these gland helps in holding two worms during copulation.

Male genital pore

  • It is found in one pair located in 18th segment.
  • Function: It acts as male genital pore.

Female Earthworm Reproductive System


  • One pair of ovaries present on 13th segments
  • Each ovary consists of several finger like processes in which ova are arranged in a linear series in various stage of development
  • Function: they form ova

Oviducal funnel

  • Each oviducal or ovarian funnel arises from both ovaries
  • Oviducal funnels appear as large saucers consisting of ciliated margins
  • Function: ova enter through oviducal funnel and travel backward along the oviduct.


  • Each ovarian funnel continues into the oviduct.
  • Oviducts open on female genital pore in the 14th segment
  • Function: they collect ova from ovary and give to female genital pore.


  • Spermathecae are 4 pairs – one pair each in the 6th, 7th, 8th, and 9th segments.
  • The spermatheca opens to the exterior via small ducts
  • Function: spermatheca is to receive and store spermatozoa from another earthworm during copulation

Female genital pore

  • It is a single unpaired small pore, lies in 14th segment.


  • During copulation two earthworms come closer and are ventrally attached in opposite direction
  • Both worms remain united together by the secretion of accessory glands and also by mutual penetration of setae in each other’s body
  • Sperm and prostatic fluid of each worm are exchanged and released or stored in spermathecae through spermathecal pore
  • Copulation lasts for about an hour
  • Fertilization is thus external, taking place in the cocoons.

Cocoon Formation In Earthworm

  • Cocoon formation takes place after copulation, when ovaries mature.
  • The epidermis of clitellar region contain 3 kinds of gland
    1. Mucous gland: produce mucus
    2. Cocoon secreting gland: secrete wall of cocoon. Also secrete a gelatinous viscid and sticky substance
    3. Albumen gland cell: produce albumen; serves for nourishment of the growing embryo
  • These gland secretion soon harden on exposure to the air, into a tough but elastic tube which is called cocoon or egg capsule.
  • Worm starts to wriggle behind so that the girdle slipped forward
  • Girdle pass over the female genital pore, it receives ova and when it passes over spermathecal, it receives sperm through spermathecal pores
  • The girdle is thrown off from the anterior end and soon the elasticity of its wall closes up two ends to form a cocoon or ootheca.


  • Fertilization takes place inside the cocoon, where each ovum is fertilized by sperm.
  • Albumen cells provide nutrition to the embryo
  • Young one hatch out after 2-2.5 months
  • Development is direct without any larval stage.

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