Ascidia mentula is a species of solitary tunicate. It is found in the north east Atlantic Ocean, the Mediterranean Sea and Black Sea. It occurs round the coasts of Britain but is seldom seen on the east coast of England or Scotland. Ascidia mentula has a tough leathery envelope or tunic composed partly of cellulose. The translucent tunic encloses a fluid-filled body with irregular bulges and two unmistakable siphons.

Salpa maxima also arrived in the upper Tyrrhenian Sea or lower Ligurian Sea, that is, in the waters of Livorno and the province where we often dive. It is a Tunicate; at first sight it looks like a cross between a fish and a jellyfish but it is neither, it is actually a transparent invertebrate belonging to the order of the Salpidae subphylum Tunicata, coming from the deepest oceans and very rare in the Mediterranean....