Prosthiostomum siphunculus (Delle Chiaje, 1822) Lang, 1884

(Fig. 2 j)

Habitat. 5 specimens were collected from mussel beds, 10 others specimens were found among algae.

Locality. Bizerta lagoon (37° 13' 19.29" N; 9° 55' 49.94" E), Port de Prince (36° 52' 25.87" N; 10° 39' 57.06" E), Errimel beach (36° 52' 25.87"N; 10° 39' 57.06" E).

Localities in Tunisia from bibliography. Port de Prince, Errimel beach (Gammoudi et al. 2011, Gammoudi and Tekaya 2012, Gammoudi et al 2012a).

Other localities in the world. This species has a broad world distribution as it was recorded from the Mediterranean: Gulf of Naples (Lang 1884); Egypt (Steinböck 1937); Catalan coasts (Novell 2001, Gammoudi & Tekaya 2011); Spanish, Italian, Greek and Corse coasts (Gammoudi et al. 2012a); European Atlantic coasts (Noreña et al. 2014); the Tyrrhenian Sea, also from South Africa, Somalia and Vietnam (Prudhoe 1985) and Japan (Kato 1937).