*thalassophila (Bagnall, 1939)
R.S. Bagnall is still the only person to have collected Friesea acuminata from UK/Eire. This distinctive species is yellow in life and possesses six anal spines (Fig. 1). The furca is small and there is a distinct mucro on the dens (Fig. 2). Specimens collected by Bagnall from littoral sites in Ireland, South Wales and southern England reach 1.9 mm in length. Although scarce, Friesea acuminata is sure to turn up in many more sites in its current range. However, it may be a 'southern' species. Friesea acuminata is unlikely to have escaped the beady eye of Bagnall in his well-worked seashore sites in Scotland and NE England. Friesea acuminata has not been recorded from Fennoscandinavia (Fjellberg 1998).
Species of Friesea have 8+8 ocelli but no post-antennal organ (PAO) or empodium on the foot (Fig. 3).