In order to develop efficient aquaculture of the Chilean muricid snail Chorus giganteus, hormonal induction of egg laying and subsequent development were investigated. Extracts of circumesophageal ganglia caused laying of both hard and soft capsules, no more than one capsule/injection. Control injections did not cause laying. The inducing substance was resistant to boiling (as are neuropeptide egg-laying hormones in Lymnaea, Aplysia, and Busycon). Median injection/laying latency was 4 - 5 hr, and 24 of 25 induced capsules contained eggs--up to 3000 eggs/capsule. Eggs in soft capsules were subject to infection; however, eggs in some hard capsules developed into veliger larvae by 49 days (time of fixation). Differences in capsule wall structure being studied by e.m. may underlie the protective effect of capsule hardening. This study demonstrates that laying of viable eggs can be induced in C. giganteus by a putative egg-laying hormone, possibly similar to hormones in Lymnaea, Aplysia, and Busycon. Supported by NSF#9724918 and FONDAP/DID-UACH S199951.