The genus Nerocila is rediagnosed, and the Australian species revised and redescribed in full. Species represented are Nerocila orbignyi (Guérin-Méneville), N. congener Miers, N. phaiopleura Bleeker, N. barramundae n. sp., N. lomatia n. sp., N. monodi Hale, N. serra and Nerocila sp. The genus Emphylia Koelbel is synonymised with Nerocila. The new genus Creniola is created for the species C. laticauda (Schiödte & Meinert), C. saurida (Avdeev), and C. breviceps (Schiödte & Meinert) from Hawaii.
Several new synonymies are reported: Nerocila cebuana Schiödte & Meinert and Nerocila philippinensis Bovallius are synonymised with N. congener; Nerocila laevinota Miers is synonymised with N. sundaica Bleeker; Nerocila maculata, N. affinis, N. adriatica, N. australasiae, N. cephalotes, N. macleayii, N. neapolitana, N. novaezelandiae, N. tartowskii, N. trailli, N. laticeps, N. vittata and Rosca rogans are placed in synonymy with Nerocila orbignyi. The history of Nerocila orbignyi is fully discussed, and the species is distinguished from related species. The following species are regarded as nomina dubia: N. aculeata Dana, N. aculeata Edwards, N. falklandica Cunningham, N. brasiliensis Dana, N. latiuscula Dana, N. tenuipes Dana, N. brongnartii (Risso) and N. cuspidata Costa. The subfamily Anilocrinae Schiödte & Meinert is rediagnosed. Host preferences, morphological variability and distribution are discussed.
Notes and some figures are given on other poorly known Indo-Pacific genera, and a list of all species of Nerocila is provided. A key to the Indo-Pacific genera of Anilocrinae, and keys to the Australian species of Nerocila and Creniola are provided.