The eggs and hatching stages of some New Zealand prosobranch molluscs

Abstract Early stages in the life history of 23 New Zealand prosobranchs from Otago waters are reviewed on a family basis. The egg capsules of 6 species, and the newly‐hatched stages of 12 species, are drawn and described for the first time. Identification of veligers from local plankton hauls showed that 6 additional species have a planktonic ve1iger stage. The most significant results are that two of the four Otago calyptraeids have direct development and the muricid Zeatrophon ambiguus (Philippi) has indirect development with a long planktonic phase. The eggs of Trichosirius inornatus (Hutton) hatch as free‐swimming echinospira larvae. In Maoricoipus roseus (Quay and Gaimard) the eggs are retained in the mantle cavity of the female, probably until they hatch as crawling fry.