Two new species of tubularian hydroids from southern Australia are described. Hybocodon cyrptus, sp. nov. is the 4th recorded species of this rare genus, and a 1st record of the genus from Australia. Ralpharia coccinea sp. nov. is the 2nd species of a genus known only from Australia. Notes are given on the ecology of both species and on the reproduction of R. coccinea.Descriptors: HYBOCODON new record; HYBOCODON CYRPTUS new species; RALPHARIA COCCINEA new speciesfigs 1-18.