Ascidiella aspersa (Müller, 1776)
Ascidiidae

Ascidiella aspersa (left), Styela clava (right) and Ciona intestinalis (right)

Locality:
Oosterschelde, The Netherlands

Literature for identification (localities mentioned):
Hayward & Ryland, 1995; p. 705 (Norway to Mediterranean)
Nagabhushama & Krishnamoorthy, 1992; (India)