Williamia is a genus of small sea snails or false limpets, marine pulmonate gastropod molluscs in the family Siphonariidae, the false (air-breathing) limpets.Bouchet, P.; Gofas, S. (2011). Williamia Monterosato, 1884. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=138490 on 2011-02-08
Their development is similar to other Siphonariids.Collin, Rachel. 2000. The development of three heterobranch mollusks from California, USA. The Nautilus, 114(3): 117-119.
Species Species within the genus Williamia include: Williamia eximia (Nevill in G. & H. Nevill, 1869) Williamia gussoni Costa, 1829 Williamia krebsii (Mörch, 1877) Williamia magellanica Dall, 1927 Williamia peltoides (Carpenter, 1864) - shield false limpet Williamia radiata (Pease, 1860) Williamia subspiralis (Carpenter, 1864)
Species brought into synonymy: Williamia galapagana Dall : synonym of Williamia peltoides (Carpenter, 1864) Williamia gussonii (O. G. Costa, 1829): synonym of Williamia gussoni (Costa O. G., 1829) Williamia japonica Habe, 1962: synonym of Williamia radiata (Pease, 1860) Williamia kermadecensis (Iredale, 1912): synonym of Williamia radiata (Pease, 1860) Williamia nutata (Headley, 1908): synonym of Williamia radiata (Headley, 1908) Williamia oblongata (Yokoyama, 1926): synonym of Siphonacmea oblongata (Yokoyama, 1926) Williamia polynesica Rehder, 1980: synonym of Williamia radiata (Pease, 1860) Williamia radiata Kuroda & Habe, in Habe, 1961: synonym of Williamia radiata (Pease, 1860) Williamia tomlini (Robson, 1913): synonym of Aporemodon tomlini Robson, 1913
References
Discover Life Marshall B.A. (1981) The genus Williamia in the western Pacific (Mollusca: Siphonariidae). New Zealand Journal of Zoology 8: 487-492