{_Planocera_ { (Fig. 8, A). {_Planocera folium_ {_Imogine._ { Grube. Berwick-on- PLANOCERIDAE. {_Conoceros._ { Tweed. With dorsal tentacles. {_Stylochus._ {_Stylochoplana maculata_ Mouth sub-central. {_Stylochoplana_ { Quatref. Among brown { (Fig. 8, B). { weeds in Laminarian {_Diplonchus._ { zone. {_Planctoplana._ {_Leptoplana tremellaris_ {_Discocelis._ { O. F. Müll. LEPTOPLANIDAE. {_Cryptocelis._ {_L. fallax_ Quatref. Without dorsal tenta- {_Leptoplana._ { Plymouth. cles. Penis directed {_Trigonoporus._ {_L. droebachensis_ Oe. backwards. {?_Polypostia_ { Plymouth Sound. { (see p. 27). {_L. atomata_ O. F. Müll. { Doubtful species. CESTOPLANIDAE. {_Cestoplana_ (Fig. 8, C). No tentacles. Body { In Mediterranean and elongated. Penis { on French side of the directed forwards. { Channel. ENANTIIDAE. { No sucker. No tenta- { cles. Main-gut very {_Enantia._ short. External { Adriatic Sea. apertures as { in _Euryleptidae_. { COTYLEA. ANONYMIDAE. { Mouth central. No {_Anonymus_ (Fig. 8, D). tentacles. With two { Naples (two specimens). rows of penes. { PSEUDOCERIDAE. {_Thysanozoon_ (Fig. 8, E). Marginal tentacles {_Pseudoceros._ folded. Mouth in {_Yungia._ anterior half. { {_Prostheceraeus vittatus_ { Mont. On west coast. {_P. argus_ Quatref. { Guernsey. EURYLEPTIDAE. {_Prostheceraeus._ {_Cycloporus papillosus_ Tentacles usually {_Cycloporus._ { Lang. On Ascidians in present and pointed, {_Eurylepta._ { 2-30 fms. or represented by two {_Oligocladus._ {_Eurylepta cornuta_ groups of eyes. Mouth {_Stylostomum._ { O. F. Müll. On sponges close to anterior end. {_Aceros._ { and shells, 2-10 fms. Pharynx cylindrical. { {_Oligocladus sanguinolentus_ { Quatref. {_O. auritus_ Clap. Doubtful. {_Stylostomum variabile_ { Lang.