E. f. has a clitellum that is normallly 26-32, but may begin on segment 24 or 25.  This may not be enough to id them, unless they are in a situation with very few other species.

I admit the answer of Dr.Wolff

 Thanks Dr Robert. I examined a species which I was told E. foetida. But the clitellar position is about 13-17. How can it be explained?

You probably have a native Indian earthworm of the family Megascolecidae, and not the European Eisenia.  I am sorry, but I am not familiar with the identification of this family or Indian earthworms.

Dr Robert, thanks for the information. I need to confirm which species I have in stock

Dear Lakshmi

Your record is not E. fetida. Other species such as Dendrobaena veneta or D. hortensis are very similar to E.fetida. Difference between  them are setal arrangement in external characteristics. 

I attached  a book for you in attachment that can help you.

Have in your mind that you can not find a species with only clitellum. Other external and internal characteristics are important.

You can find E.fetida in pile of cow dung.  Colour dark violet sometimes alternating stripes of darker segmental with paler intersegmental areas.

I would still focus on Megascolecidae or other native earthworms.  Lumbricidae such as Dendrobaena are not as likely.

Yes. It can belongs to Megascolecidae such as :

Pontodrilus litoralis (Grube, 1855)

or 

Perionyx excavatus (Perrier, 1872)

Thanks for the information mohammad

Only Clitellum position is not sufficient to identify the species. The position of spermathecal pore is very important. In eisenia fetida it is dorsal in position and two in numbers. Three in case of eisenella tetradra.