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Three new species of the cyclopoid copepod Halicyclops are described from river estuaries of Ariake Bay, Japan. Halicyclops continentalis sp. nov. is most similar to H. laminifer, but differs by the shape of an angular protuberance on the genital double‐somite and a serrate hyaline frill of the fourth urosomite. Halicyclops sinensis described by Tai and Chen is widely distributed in China and is identifiable to H. continentalis, indicating that the population in Ariake Bay is probably a continental relict. Halicyclops uncus sp. nov., belonging to the thermophilus group, is distinguishable by the shape of the lateral process on the genital double‐somite, a frill of the fourth urosomite and caudal rami; it is probably endemic to Japan. Halicyclops ariakensis sp. nov. differs from the other congeners by a combination of the shape of the prosome, urosomal hyaline frills and caudal ramus length; it is considered endemic to Ariake Bay.

A number of harpacticoid and cyclopoid copepods were collected during two short-term studies examining the effects of organic enrichment on the distribution and density of meiofauna in two coastal systems in central (Ensenada del Pabellon lagoon) and southern (Urias system) Sinaloa, north-western Mexico. Harpacticoids were by far the most common Copepoda, followed by cyclopoids and poecilostomatoids. The present contribution provides the complete description of a new species of the so far monotypic genus Kristensenia Por, 1983, known from Bonaire (Netherlands Antilles) and Celestun lagoon (Yucatan, Mexico), and the first record and range extension of Halicyclops hurlberti Rocha, 1991, previously known from Tihuana estuary near San Diego (California, USA). An updated generic diagnosis for Kristensenia Por, 1983 is presented.

Halicyclops cenoticola sp. nov. is described from cenotes of the Yucatan Peninsula, Mexico. The new species shares exclusively with H. caridophilus and H. tetracanthus the presence of 2 inner setae on the leg 5 exopod in the males. As far as is known, the new species is distinguished trom all its congeners in having the dorsal caudal seta as long as the outer middle caudal seta; legs 2 and 3 are dimorphic concerning the structure of the 3 inner setae on the terminal endopodal segment; and leg 6 of both the male and female consists of only 2 elements. An identification key for the Halicyclops species known trom the Caribbean Region, the Gulf of Mexico, Bermuda, and the coast of French Guiana is included.

A new species of Speleoithona and two new species of Halicyclops are described from plankton samples taken in anchialine caves in Bermuda. Halicyclops ytororoma, previously known from interstitial intertidal waters along the coast of the State of Sao Paulo, Brazil, is also found in these troglobiont samples. Speleoithona is redefined to contain the new species from Bermuda.

SUMMARY Two species of Cladocera and eight species of Copepoda (Crustacea) are reported from Somalia; six are first records for that country. No species are new to science. Besides a few that appear to be endemic to North-East Africa, several are interesting range extensions. Halicyclops thermopbilus Kiefer, 1925, a brackish-water species fringing the coasts of the Indian Ocean, is figured in detail.