Ten new glycosphingolipids, halicylindrosides A(1)-A(4) (1-4) and B-1-B-6 (5-10) have been isolated from the Japanese marine sponge Halichondria cylindrata. Their structures were determined by spectroscopic and chemical methods. These cerebrosides were moderately antifungal against Mortierella remanniana, and cytotoxic against P388 murine leukemia cells.