On two hollinid ostracode genera from the Upper Carboniferous of Northwestern Spain

This paper describes some features of the carapace of two hollinid ostracode genera: Hollinella and Jordanites. The carapace of these ostracodes consists essentially of the same layers as modern ostracodes, with exception of the velar structures. A survey on the ontogeny of species of Hollinella and Jordanites reveals that this is very similar to the ontogeny of other palaeocopid ostracodes. It is suggested that Hollinella and Jordanites were marine near-bottom swimmers. The velum probably served to prevent the animal from sinking too deeply into a soft substrate. Five species of Hollinella, including three new species, and three species of Jordanites are described. All species are restricted to the Upper Carboniferous of NW Spain.