Reginald Victor

Achiasmatic meiosis and complex heterozygosity in female cyclopoid copepods (Copepoda, Crustacea)

In Mesocyclops edax S.A. Forbes, 2n=14, a North American copepod, the females are heterozygous for several interchanges leading to the formation of large rings of chromosomes (rings of 14, or of 12 plus 1 bivalent) at meiotic metaphase, comparable to those of the plant Oenothera, although no chiasmata are present. The chromosomes are more or less metacentric and have large terminal H-segments. In the rings homologous arms are held together by connecting fibers which insert close to the euchromatin-heterochromatin junctions. Coordinated orientation of the zigzag type seems to be the role.

Drift of ostracod crustaceans in adjacent intermittent and permanent streams

Ostracods were studied in the drift of adjacent permanent and intermittent streams in Southern Ontario. More species were drifting in the permanent stream than in the intermittent one. The latter developed a pool fauna during early summer and stagnant water species were predominant. Both standing and running water species were common in the permanent stream. Eleven were recorded in the drift and all but one of them are strong swimmers. I. bradyi, the only poor swimmer usually lives among vegetation and it is suggested that truly herpobenthic ostracods are less subject to drift than the others. The pattern of ostracod drift over a period of 13 months in those streams was different. The numbers drifting at the upstream and downstream stations of the same stream in a given month was variable. Ostracods were the major component of crustacean drift in both streams. Stream drift is considered as a mechanism of ostracod dispersal.

Description of a new species of the genus Hungarocypris Vavra, 1906 (Crustacea : Ostracoda) from Sulawesi, Indonesia, with a discussion on the distribution of the genus

A new species of the genus Hungarocypris Varvra, 1906 is described from Sulawesi, Indonesia. This is the third known living species for the genus. At present four extinct and three extant species are known for Hungarocypris and a discussion is given on its global distribution.

A New Species of Ilyodromus Sars (Crustacea, Ostracoda) from the Philippines

The genus Ilyodromus Sars, 1895 is recorded for the first time in the Oriental Region. Ilyodromus lanaoensis sp. n. is described from Mindanao, the Philippines and compared with the other species of the genus for differential diagnosis.

Redescription of two freshwater ostracods (Crustacea, Ostracoda) of the genus Eucypris Vavra, 1891 from the Philippines

The type specimens of the freshwater ostracodsEucypris bayensis Tressler, 1937 andEucypris orca Tressler, 1937, from the Philippines are redescribed and their valves and appendages are figured.