Type species. Dondersia festiva Hubrecht, 1888, Mediterranean Sea 60 m. Other species: D. annulata Nierstrasz, 1902, Indian Ocean (Indonesia) 38 m; D. cnidevorans Salvini-Plawen, 1978, Antarctic 659–717 m; D. ? laminata Salvini-Plawen, 1978, Antarctic 311‾ 426 m; D. ? stylastericola Salvini-Plawen, 1978, Antarctic 300 m; D. namibiensis Scheltema, Schander & Kocot, 2012, South East Atlantic 619 m. D. incali (Scheltema, 1999), North East Atlantic 2091 m. D. todtae Klink, Bergmeier, Neusser & Ĵrger, 2015, East Atlantic, Azores Islands, 60 m.
Diagnosis. Elongate body without keel. Anterior end tapered to beaklike point, posterior end with a fingerlike projection and with a posterior lobe (in mature specimens). Leaf-shaped scales most abundant type of sclerites with oar-shaped (= pallet-shaped) or laminar scales scattered between them. With or without common atrio-buccal cavity. Monoserial radula; teeth with four denticles; two central denticles fused and curved distally; two lateral, outswung, curved denticles arising from rounded, serrated base. With or without dorsoterminal sensory organ. With or without copulatory stylets. Without respiratory folds. With seminal vesicles.