The Middle Ordovician of the Oslo Region, Norway: 30. The eocrinoid genera Cryptocrinites, Rhipidocystis and Bockia

Eocrinoids are recognized in the Oslo Region for the first time, and comprise three genera: Cryptocrinites, Bockia and Rhipidocystis. Six new species Bockia mirabilis, Bockia grava, Bockia heintzi, Bockia sp. A, Cryptocrinites? similis and Rhipidocystis norvegica are established. The fauna is similar to that of lngennanland and Estonia in the USSR. The restricted stratigraphical and geographical distribution of individual species shows a high degree of specialization of these taxa. The appendages of Rhipidocystis norvegica and Bockia mirabilis are well preserved. Bockia has erect biserial pinnate 'arms' with biserial brachioles, a unique feature of food-gathering appendages in primitive echinoderms. The class Eocrinoidea does not form a natura! unit in its present taxonomic state. The wide spectrum of morphological characters present confuses rather than clarifies the taxonomic relationship between members of the class.