New spicular skeletons in Turbellaria, and the occurrence of spicules in marine meiofauna1

With Florianella, Bertiliella and Acanthiella, three new genera of Turbellaria are described, one from deep mud bottoms off Norway, and two from sandy bottoms off the south-eastern United States. Whereas the new family Bertiliellidae (within Turbellaria-Eukalyptorhynchia) is established for the two former genera, the latter is of uncertain systematic position, combining features of Archoophora and Prolecithophora-Combinata. All three genera are characterized by a spicular skeleton located in the basement membrane. In the Bertiliellidae the spicules are calcareous (aragonite). A survey of other spiculiferous Turbellaria and meiofauna in general suggests that spicular skeletons, instead of being a special adaptation to the interstitial environment, play a role in body support and tissue economy, and are, in some cases (Turbellaria and Mollusca), possibly relics indicating phylogenetic relationship.