Cephalopyge
Cephalopyge is a genus of pelagic nudibranchs comprising the single species Cephalopyge trematoides, a free-swimming marine gastropod in the family Phylliroidae.
Etymology
Cephalopyge is a contraction of cephalus and referring to the position of the anus close to the head. The species epithet trematoides expresses a likeness to flukes.Description
Cephalopyge trematoides grows to in length. It swims at approximately, by passing several undulatory waves down its body each second. It is flattened and transparent; its internal organs are visible.Pelagic nudibranchs
Of the approximately 3000 species of nudibranch, the vast majority are benthic, only a couple are neustonic, and Cephalopyge trematoides is very unusual in that it is pelagic. It is estimated to be one of only five planktonic nudibranch species.Further information :