Hi Oussama,

an older classis publication might be the most comprehensive guide for polychaetes from Morocco:

Pierre Fauvel (1936) Contribution a la Faune des Annelides Polychetes Du Maroc.

The full publication can be found here:

http://www.annelida.net/docs/Fauvel1936_ContrFaunaAnnPolychetesMarocOCR.pdf

Thank You Michael 

but i want  a key to species not necessery in morocoo , just  a good classic identification key 

A good key up to genus level is the famous "pink book" by Fauchald, which can be found here:

www.vliz.be/imisdocs/publications/123110.pdf

The taxonomy is, of course, not quite up-to-date anymore, as the book is almost 40 years old. But, it is still very useful.

I also like the interactive key by Wilson, Hutchings & Glasby, which can be purchased online. This key has the advantage that you chose the morphological characters that you use.

For species level identification, you will have to work with the original descriptions of the respective genera.

thank you Michael for your reply and for the informations 

Dear Oussama Bououarour,

You can try Fauvel by following link's

Best Regards,

http://www.faunedefrance.org/bibliotheque/docs/P.FAUVEL(FdeFr16)Polychetes-sendentaires.pdf

http://www.faunedefrance.org/bibliotheque/docs/P.FAUVEL(FdeFr05)Polychetes-errantes.pdf