| Convoluta punctata Riedl, 1959 | 1952 | litoral |  | litoral and marine caves. | 
| Convoluta sordida Graff, 1882 | 1878 or 1879 |  |  |  | 
| Convoluta cinereus Graff, 1874 | 1878 or 1879 |  |  |  | 
| Convoluta paradoxa Ørsted, 1843 | prior to 1882 |  |  |  | 
| Mesostoma neapolitanum Graff, 1882 | prior to 1882 |  |  | 1 speciment found between Ulven | 
| Macrorhynchus naegelii (Kölliker, 1845) | prior to 1882 |  |  |  | 
| Hyporhynchus setigerus (Schmidt, 1852) | prior to 1882 |  |  |  | 
| Hyporhynchus penicillatus (Schmidt, 1857) | prior to 1882 |  |  | everywhere but rare | 
| Anoplodium schneideri Semper, 1868 | prior to 1882 |  |  |  | 
| Solenopharynx flavidus Graff, 1882 | prior to 1882 |  |  | 2 specimens in Ulven (Ulva lactuca). | 
| Plagiostomum maculatum Graff, 1882 | prior to 1882 |  |  | in Ulven (Ulva) . | 
| Plagiostomum reticulatum (Schmidt, 1852) | prior to 1882 |  |  | in Ulven (Ulva) | 
| Vorticeros auriculatum (Müller, 1784) | prior to 1882 |  |  |  | 
| Vorticeros luteum Hallez, 1879 | prior to 1882 |  |  |  | 
| Monotus lineatus Müller, 1773 | prior to 1882 |  |  |  | 
| Monotus bipunctatus (Leydig, 1854) | prior to 1882 |  |  |  | 
| Proporus venenosus (Schmidt, 1852) | 1878 or earlier |  |  |  | 
| Aphanostoma diversicolor Ørsted, 1845 | 1882 or earlier |  |  |  | 
| Convoluta paradoxa Ørsted, 1843 | 1866 or earlier |  |  |  | 
| Plagiostomum girardi (Schmidt, 1857) | 1955 or earlier |  |  |  | 
| Hofsteniola pardii Papi, 1957 | Oct, Nov 1955 | 2-8 m |  | very rare and difficult to find even in areas where it has been found.  Found on the plant Posidonia. | 
| Haplodiscus ussowi Sabussow, 1896 | 1889 | pelagic |  |  | 
| Trigonoporus cephalophthalmus Lang, 1884 | prior to 1884 |  |  | Melobesia zone of Secca di Gajola, Bay of Naples, Italy | 
| Anonymus virilis Lang, 1884 | prior to 1884 |  |  |  | 
| Planaria siphunculus Delle Chiaje, 1822 | prior to 1928 |  |  |  | 
| Graffilla muricicola Ihering, 1880 | 1913 or earlier |  |  | in the kidney of Murex trunculus L. and Murex brandaris L.  Parasite. | 
| Umagilla forskalensis Wahl, 1909 | 1906 or earlier |  |  | gut of Holothuria forskalii. | 
| Umagilla forskalensis Wahl, 1909 | 1953 or earlier |  |  | gut of Holothuria forskalia. | 
| Syndesmis echinorum Francois, 1886 | 1913 or earlier |  |  | in sea urchins [Strongylocentrotus droebachensis (Müll.), S. lividus Brdt., Sphaerechinus granularis A.Ag., Echinus sphaera Müll., E. acutus Lam.] | 
| Anoplodium parasita Schneider, 1858 | 1953 or earlier |  |  | parasite in Holothuria tubulosa and Stellata. | 
| Anoplodium gracile Wahl, 1906 | 1953 or earlier |  |  | parasite in Holothuria forskalii. | 
| Anoplodium gracile Wahl, 1906 | 1906 or earlier |  |  | parasite in Holothuria forskalii Chiaje | 
| Anoplodium graffi Monticelli1892 | 1892 or earlier |  |  | parasite in Holothuria impatiens Gm. | 
| Collastoma minutum Wahl, 1906 | 1906 or earlier |  |  | in the gut of Phymosoma granulatum F.S. Leuckart. | 
| Typhlorhynchus nanus Laidlaw, 1902 | 1902 or earlier |  |  | ectoparasite on Nephthys scolopendroides Chiaje | 
| Promesostoma marmoratum (Schultze, 1851) | 1913 or earlier |  |  | very active, in marine and brackish water. | 
| Promesostoma marmoratum marmoratum (Schultze, 1851) | 1913 or earlier |  |  | very active, in marine and brackish water. | 
| Promesostoma marmoratum nudum Graff, 1905 | 1913 or earlier |  |  |  | 
| Promesostoma ovoideum ovoideum Graff, 1905 | 1913 or earlier |  |  |  | 
| Promesostoma solea solea Graff, 1905 | 1913 or earlier |  |  |  | 
| Paramesostoma neapolitanum (Graff, 1882) | 1913 or earlier |  |  |  | 
| Polycystis mamertina (Graff, 1874) | 1913 or earlier |  |  |  | 
| Prostomum immundum Schmidt, 1857 | 1857 or earlier |  |  |  | 
| Mesostomum chlorosticum Schmidt, 1857 | 1857 or earlier |  |  |  | 
| Plicastoma bimaculatum (Graff,1882) | 1913 or earlier |  |  |  | 
| Mecynostomum filiferum Ax, 1963 | Apr 1958 | 4 m | sand | Reiner Mittelsand aus 4 m Wassertiefe, vor "Villa Galotti". | 
| Boreocelis urodasyoides Ax, 1963 | Apr 1958 | 4 m | sand | Reiner Mittelsand aus 4 m Wassertiefe, vor "Villa Galotti". | 
| Heterochaerus langerhansi (Graff, 1882) | 1952 |  |  | marine caves. | 
| Tyrrheniella sigillata Riedl, 1959 | 1952 | 1.0-1.2 m |  | marine caves. | 
| Planocera graffi Lang, 1879 | 1884 or earlier |  |  | associated with Balanus, Halichondria, Penares, Lithodomus, Halichondria-Astroides. | 
| Prosthiostomum siphunculus (Delle Chiaje, 1822) | 1828 or earlier |  |  | associated with Posidonia. | 
| Leptoplana pallida (Quatrefage, 1845) | 1845 or earlier |  |  | associated Halimeda-Peyssonelia, Euspongia-Lithodomus. | 
| Planocera graffi Lang, 1879 | 1884 or earlier |  |  | associated with Balanus, Halichondria, Penares, Lithodomus, Halichondria-Astroides. | 
| Ceratopera gracilis (Graff, 1882) | Mar 1958 |  |  | "Villa Rendel", between Posidonia and algae (Caulerpa, Cryptonemia u.a.).  Few specimens. | 
| Archimonocelis mediterranea Meixner, 1938 | 1938 or earlier |  |  | Type material was stored the Zoological Museum of Berlin and destroyed during the Second World War. | 
| Sopharynx typhlops Beklemischev, 1929 | 1929 or earlier |  |  |  | 
| Lenopharynx languidus Beklemischev, 1929 | 1929 or earlier |  |  |  | 
| Cestoplana raffaelei Ranzi, 1928 | 1928 or earlier |  |  |  | 
| Anoplodium pusillum Monticelli, 1892 | 1892 or earlier |  |  | from body cavity of Holothuria poli. | 
| Typhlorhynchus nanus Laidlaw, 1902 | 1902 or earlier |  |  | from Nephthys scolopendroides. | 
| Cerbussowia cerruti Wilhelmi, 1909 | 1909 or earlier |  |  |  | 
| Planaria nesidensis Delle Chiaje, 1822 | 1822 or earlier |  |  | Gulf of Genua and Nizza, Italy. | 
| Prostheceraeus violaceus (Delle Chiaje, 1822) | 1822 or earlier |  |  |  | 
| Pseudoceros muelleri (Delle Chiaje, 1829) | 1829 or earlier |  |  | Naples, Gulf of Naples. | 
| Macrostomum parthenopeum Beklemischev, 1951 | 1951 |  |  |  | 
| Haplodiscus ussowi Sabussow, 1896 | 1905 or earlier |  |  | Golf von Neapel und Messina. | 
| Proporus venenosus violaceous Graff, 1882 | 1882 or earlier |  |  | Mittelmeer (Neapel). | 
| Otocelis rubropunctata (Schmidt, 1852) | 1905 or earlier |  |  | Mittelmeer (Neapel) | 
| Syndesmis echinorum Francois, 1886 | 1895 or earlier |  |  | from Sphaerechinus granularis (Toxopneustidae). | 
| Cestoplana faraglionensis Lang, 1884 | 1884 or earlier |  |  |  | 
| Discocelis tigrina (Blanchard, 1847) | 1884 or earlier |  |  |  | 
| Thysanozoon brocchii (Risso, 1818) | 1933 or earlier |  |  |  |