Velutinidae

Velutinidae is a family of small sea snails, marine gastropod molluscs in the clade Littorinimorpha.

The shell of these animals is very thin and delicate, and internal, completely covered by the mantle (which has fused lobes) so the appearance of these animals more closely resembles that of sea slugs rather than sea snails.

Taxonomy
The following two subfamilies were recognized in the taxonomy of Bouchet & Rocroi (2005):


 * Subfamily Velutininae J. E. Gray, 1840 - synonyms: Marseniidae Leach in Gray, 1847; Marsenininae Odhner, 1913; Capulacmaeinae Golikov & Gulbin, 1990; Onchidiopsinae Golikov & Gulbin, 1990 (n.a.); Marseniopsidae Badel, 1993 (n.a.)
 * Subfamily Lamellariinae A. D. d'Orbigny, 1841 - synonyms: Coriocellidae Troschel, 1848; Sacculidae Thiele, 1929 (inv.); Pseudosacculidae Kuroda, 1933

Genera
Genera within the family Velutinidae include:
 * Calyptoconcha
 * Calyptoconcha pellucida A. E. Verrill, 1880 - translucent lamellaria
 * Cartilagovelutina Golikov & Gulbin, 1990
 * Cartilagovelutina beringensis (Derjugin, 1950)
 * Cartilagovelutina chondrina (Bartsch in Derjugin, 1950)
 * Cartilagovelutina cristata (Derjugin, 1950)
 * Ciliatovelutina Golikov & Gulbin, 1990
 * Cilifera Golikov & Gulbin, 1990
 * Coriocella Blainville, 1824
 * Echinospira Krohn, 1853
 * Lamellaria G. Montagu, 1815
 * Lamellariopsis Vayssière, 1906
 * Limneria H. Adams & A. Adams, 1851
 * Marseniella Bergh, 1886
 * Marseniella borealis Bergh, 1886
 * Marsenina Gray, 1850
 * Marseniopsis Bergh, 1886
 * Mysticoncha Allan, 1936
 * Onchidiopsis Bergh, 1853
 * Onchidiopsis glacialis M. Sars, 1851 - icy lamellaria
 * Onchidiopsis latissima Odhner, 1913
 * Onchidiopsis spitzbergensis Jensen, in Thorson, 1944
 * Piliscus Lovén, 1859
 * Piliscus commodus Middendorff, 1851
 * Piliscus rostratus (Golikov & Gulbin, 1990)
 * Piliscus undulatus (Golikov & Gulbin, 1990)
 * Pseudosacculus Hirase, 1928
 * Pseudotorellia Warén, 1989
 * Pseudotorellia fragilis Warén, 1989
 * Torellivelutina McLean, 2000
 * Velutina Fleming, 1820
 * Velutina plicatilis (Müller, 1776)
 * Velutina schneideri Friele, 1886
 * Velutina velutina (Müller, 1776)

Subfamily Lamellariinae A. D. d'Orbigny, 1841

Subfamily Velutininae Gray, 1840
 * Genera brought into synonymy:
 * Capulacmaea M. Sars, 1859 : synonym of Piliscus Lovén, 1859
 * Chelinotus Swainson, 1840: synonym of Coriocella Blainville, 1824
 * Cryptocella H. Adams & A. Adams, 1853: synonym of Lamellaria Montagu, 1815
 * Marsenia Oken, 1823: synonym of Lamellaria Montagu, 1815
 * Marvillia [sic]: synonym of Limneria H. Adams & A. Adams, 1851
 * Morvillia Gray, 1857: synonym of Limneria H. Adams & A. Adams, 1851
 * Oithonella Mörch, 1857: synonym of Marsenina Gray, 1850
 * Oncidiopsis [sic]: synonym of Onchidiopsis Bergh, 1853
 * Pilidium Middendorff, 1851: synonym of Piliscus Lovén, 1859
 * Pseudoacculus [sic]: synonym of Pseudosacculus Hirase, 1928
 * Sacculus Hirase, 1927: synonym of Pseudosacculus Hirase, 1928
 * Velutella Gray, 1847: synonym of Velutina Fleming, 1820