Four new macrolides (7-lo), structurally related to known sphinxolides (l-4) and reidispongiolides (S-6), have bean isolated following a reinvestigation of Neosiphoniu supers&s and Reidispongia coeru!ea, two Lithistida sponges collected in the deep waters off New Cakdonia. In this paper we report their structure elucidation based on spectral data (mainly ZD-NMR and MS) as well as their cytotoxicity determined on a panel of 60 human cancer cell lines (NC1 in vitro primary screen).