Nerve plexus of Nemertinea, [103], [105]

Nervous system, of Leptoplana, [13], [14];

of Polyclads, [26], [30];

of Planaria lactea, [39];

reduced in parasitic Rhabdocoels, [45];

of Temnocephala, [54];

of Polystomatidae, [56];

of Cestodes, [75], [86];

of Nemertinea, [105], [106];

of Nematoda, [127];