Strombus

1-10

Authors: Leite, F.P.P.; Tambourgi, M.R.S. & Cunha, C.M.

Seasonal variations in the composition, density and number of species of gastropod molluscs associated with fronds and sediment retained on rhizoids of the green seaweed Caulerpa racemosa were studied on two beaches on the North coast of the State of São Paulo. The two beaches have different hydrodynamics and degrees of human impact. Samples were collected at Praia das Cigarras (moderately agitated, with strong human influence) in Sebastião, and at Praia da Fortaleza (sheltered and little human influence) in Ubatuba, during the four seasons of the year (winter, spring, summer and autumn). Three samples were obtained from each beach for every season of the year. Gastropod molluscs were identified, when possible, to species level and counted. A total of 50 species were identified, and their number and composition varied according to the season of the year and the beach. Few species were dominant in both sites and all four seasons. Most of the species occurred in low number and densities, and were not always present in all seasons of the year. The physical and biological characteristics of each beach, regarding macroalgae morphology, sediment retained by rhizoids and hydrodynamics, may be the variables controlling composition, number of species, dominance and density of gastropods.

19-23

Authors: Gomes, R.S.

Marine snails of the tropical family Conidae are represented in Brazilian waters by twenty species of the genus Conus. Brazilian cones have a similar shell structure, morphological study of both soft parts and radula, when they are available, are useful in recognizing inter-specific differences. Illustrated here for the first time, is the male genital system and radular tooth of Conus carioca Petuch, 1986, using both, optical and scanning electron microscope images, contributing to the knowledge of the species.