Two novel bicyclic diterpenoides, agelasimine-A (9), and agelasimine-B (10), have been isolated from the orange spongeAgelasmauritiana. Also, a new bromine-containing alkaloid, 5-debromomidpacamide (12), along with midpacamide (13) and methylN-methyl-4,5-dibromopyrrole-2-carboxylate (11), has been isolated. The structures were determined by interpretation of their spectral data. Agelasimine-A and -B exhibit a wide range of interesting biological activities such as cytotoxicity, inhibition of adenosine transfer into rabbit erythrocytes, Ca2+-channel antagonistic action, and α1adrenergic blockade.