FEMALE GENITAL STRUCTURES IN SEVERAL FAMILIES OF CENTROPAGOIDEA (COPEPODA, CALANOIDA)

The female genital structures of 21 calanoid species belonging to the families Candaciidae, Centropagidae, Pontellidae, Sulcanidae, Temorida e and Tortanidae were studied using light and electron microscopy (sca nning electron microscopy, transmission electron microscopy). Except t he monotypic Sulcanidae, their organization conforms to a common patte rn characterized by egg-laying ducts opening through paired adjacent g onopores into a small cavity, the genital atrium, covered by a genital operculum and opening to the outside through a distal atrial slit. No seminal receptacle is present and the seminal products must be stored for a brief period in the genital atrium. The genital structures occu py a well delimited genital area, the main changes in which concern th eir position on the ventral face of the genital double-somite, and ope rculum morphology. Their organization and possible mode of operation a re compared with those of other calanoid families. A possible correlat ion between absence of seminal receptacles and mating behaviour is dis cussed.