Pelagische Prosobranchier-Larven des Golfes von Neapel

Abstract

From 915 plankton samples taken during the years 1968–1971 in the Gulf of Naples the prosobranch veliger larvae were separated and identified. The tows taken cover the entire annual cycle and were taken at different day-times and depths down to 300 m. The collection contains 68 different larval forms, 47 of which could be identified. From the remaining 21 larval forms 13 belong to a known genus whereas 8 remain unidentified. 35 larvae are here described or identified for the first time. The descriptions chiefly deal with size, shape and sculpture of the larval shell; they are completed and illustrated by photographs taken with the scanning electron microscope. It can be stated that shape and sculpture of the larval shell are very constant in many (if not all) species. In some closely related species the features of the larval shells differ more significantly than those of the adult shells and may, therefore, be of great taxonomic value. Some remarks are given on the annual occurrence and vertical distribution, the diurnal vertical migration and the behaviour of the swimming larvae.