Formation of cocoon in earthworm, Biology

Assignment Help:

Formation of cocoon in earthworm:

In earthworm segments from 14 to 17 are swollen. Skin on these segments is thick and glandular. This is called clitellum.
When ovaries mature, the clitellum secretes a viscous substance in the form of a girdle.
This girdle hardens into a cocoon around the clitellum.
Earthworm wriggles out of the cocoon - cocoon moves anteriorly and the worm moves posteriorly.
Ova are discharged into the cocoon. When the cocoon moves over the spermathecae openings. Spermatozoa received from another animal are stored in the spermathecae are discharged into it.
The cocoon finally comes out of the body and both ends of cocoon get closed.
Fertilization takes place in cocoon. Since fertilization is taking place outside the body, it is external fertilization.
After about 8 to 10 weeks, young earthworms come out of the cocoon.

981_Formation of cocoon in earthworm.png

Related Discussions:- Formation of cocoon in earthworm

What are goitrogens, What are Goitrogens? Certain chemical substances l...

What are Goitrogens? Certain chemical substances like thiocyanates, phenols, disuphides, flavanoids etc, found in the environment, can interfere with iodine metabolism. These s

Is neuron a synapses onto neuron b, Is Neuron A synapses onto Neuron B ...

Is Neuron A synapses onto Neuron B Consider Neuron B in the frog central nervous system whose plasma membrane has a newly discovered ligand-gated ionotropic receptor, named the

What is the axes of fick, What is the Axes of Fick The Axes of Fick sho...

What is the Axes of Fick The Axes of Fick show that any eye position can be specified as the amount of rotation around a set of axes fixed in the orbit: 1) Vertical Axis: Z-

What is the mendel observations and conclusions, How would Mendel's observa...

How would Mendel's observations and conclusions have been dissimilar if many of the characteristics he studied, such as seed color and seed texture, had been controlled by genes lo

Which is the brain region responsible for the coordination, Which is the br...

Which is the brain region responsible for the coordination and equilibrium of the body? In the central nervous system the cerebellum is the main controller of the motor coordin

An mrna molecule codifies only one type of protein, An mRNA molecule codifi...

An mRNA molecule codifies only one type of protein? Eukaryotic cells have monocistronic mRNA, i.e., every mRNA codifies only one polypeptide chain. Prokaryotes can present poly

Endothelium - ovule, Endothelium - Ovule In plants bearing unitegmic o...

Endothelium - Ovule In plants bearing unitegmic ovules, the nucellus degenerates during early stages of ovule development and the embryo sac comes in contact with the innermos

Paremicium, general charecter

general charecter

What do you understand by metanephridia, What do you understand by Metaneph...

What do you understand by Metanephridia? An excretory-osmoregulatory organ comprising a ciliated funnel, nephrostome, connected to tubules that lead to the external nephridiopo

Meaning of gestational diabetes mellitus, Q. Meaning of Gestational Diabete...

Q. Meaning of Gestational Diabetes Mellitus? In this type of diabetes, increased blood sugar level is first diagnosed or recognized during pregnancy. Women are not known as dia

Write Your Message!

Name

Email id

Message

Verfication Code

User Account

All Pages