We studied the Cladocera in four shallow brackish lakes at El Hondo and Salinas de Santa Pola in Mediterranean Spain fromFebruary 1999 to June 2000, sampling each month. We recorded five species : Daphnia magna, D. pulex, D. longispina,Simocephalus exspinosus and Moina brachiata. D. magna was the most abundant species and the only one present all yearround. Total abundance of Cladocera varied significantly between wetlands and months, and was highest in the largest, deepest,least saline wetlands. For a given wetland and month, abundance increased at points of greater depth or lower salinity. Speciesrichness of Cladocera was highest in those seasons and lakes where salinity was lowest, and in those seasons and lakes wherecladoceran abundance was highest. These wetlands hold a particularly high number of waterbird species, but a very low numberof Cladocera species. Ready dispersal via waterbirds does not appear to promote cladoceran diversity in this system, owingto local conditions such as high salinity. We suggest that the conservation value of wetlands for birds is not a good predictor ofvalue for Cladocera.

A new species of small cyclopoids from subterranean waters of India is described in a newly established subgenus,Kiefercyclops n.sg., of the genus Haplocyclops Kiefer, 1952. Genital double-somite with ovipores situated in the posterior half,antennula without the lateral seta on the ultimate segment, and caudal rami with the lateral seta inserted in the proximal half areamong the most important characters of H. (K.) fiersi n.sp., that warrant its position in the genus Haplocyclops. Also, the newspecies differs from the other six congeners by several autapomorphic characters, most of them being reductions in armatureand/or segmentation of the appendages. In particular, the degree of reductions concerning the segmentation of the swimminglegs makes it the most reduced free-living cyclopoid, with both rami of third and fourth legs, as well as the endopod of secondleg being one-segmented in both sexes. A key to species of Haplocyclops is given at the end of this paper.

This paper presents a description of the hitherto unknown larva of Drusus muelleri McLachlan, 1868. Information on the morphologicaland genetic identification of this species is given, and the most important diagnostic features are illustrated. Its systematicposition within genus Drusus is affirmed and some zoogeographical and ecological notes are added.

In this revision of the 25 French Protonemura, two new taxa are described : P. zhiltzovae sp. n. and P. ausonia padana ssp. n.Moreover, P. spinulosa (Navás 1921) is restored to the species level. Affinities, etymology, ecology and distribution are commentedon for each species. Identification keys and drawings are given for males and females. Finally, Protonemura distributionswithin the main French mountainous massifs are discussed.

Chemical, chemical-physical and biological procedures were employed to carry out a hydrobiological study of a reservoir inthe central Apennines (Italy), designed for the supply of drinking and irrigation water, and tourist recreation facilities.Potentiometric, volumetric, spectrophotometric, and chromatographic techniques were used for the chemical-physical analyses,while the OECD method was adopted to assess the trophic level. The phosphorus and chlorophyll values evidenced the oligomesotrophiccondition of the reservoir, with a dominance of the oligotrophic level. The analysis of the net-phytoplankton communityshowed the prevalence of the oligotrophic level, with a smaller tendency to the mesotrophic one. The dominant specieswere Dinobryon divergens Imhof and D. sertularia Ehrenb. among the Chrysophyceae, and Ceratium hirundinella (O.F. Müll.)Dujardin and Peridinium cinctum Ehrenb. among the Dinophyceae. However, some potentially dangerous inocula (Planktothrixagardhii (Gom.) Anagnostidis et Komárek and Microcystis aeruginosa (Kütz.) Kützing were present, suggesting that the reservoirshould be kept under accurate observation.

Ten species of molluscs were identified in the freshwater tidal area of the River Minho estuary. Species richness per site rangedfrom 1 to 9. Abundance ranged from 230 to 4130 individuals per m², with an average of 1412 individuals per m2. Corbiculafluminea(Müller, 1774) presented the highest density, corresponding to 88.7 % of the total specimens gathered, followed byPisidium amnicum (Müller, 1774) with 5.8 %. Biomass ranged from 17.0 to 249.6 g AFDW m-2, with an average of 99.8 gAFDW m-2. C. fluminea was the species dominating the total biomass (95.4 %), followed by Bithynia tentaculata (Linnaeus,1758) with 1.6 %. A multivariate analysis revealed a community with two distinct groups : one group almost or exclusivelyrepresented by C. fluminea, and another group with a more diverse assemblage.