Abstract
The paper deals with the genera Spirontocaris, Lebbeus, Eualus and Thoralus, with eight species (see Contents), their systematic position, and their occurrence along the Norwegian roast. S. lilljeborgi, L. polaris and E. pusiolus are common in the whole area. T. cranchii and E. occultus are frequently found in southern Norway. E. occultus is recorded for the first time from Norway. S. spinus, S. phippsi and E. gaimardii are common in north Norway, having their southern limit in western Norway. A key to the Norwegian species is given, and a short note on the two parasitic isopods found.