Three Capitellidae (Polychaetous Annelids) issued from the Mediterranean's Occidental and Oriental basins are analysed in the present work. These are
Notomastus aberans Day,
Notomastus formianus Eisig and
Peresiella clymenoides n. gen., n. sp.
N. aberans was known from South Africa and this record is the first from the Northern Hemisphere.
N. formianus had not been recorded since the Eisig's discovery, in 1887. A new genus and a new species are erected:
Peresiella lumbricoides [sic].