Über parasitische Polychaeten in Kreide-Austern sowie einige andere in Muschelschalen bohrende Würmer

Shells of oysters from Turonian strata in Westphalia contain dwelling tubes of polychaete worms sunk into the shell material. The roofs of the tubes consist of shell material secreted by the oysters. Thus the tubes are intra vitam deformations of the shell, resembling the "mudblisters" of recent oysters. Usually, they are directed centripetally towards the muscle scar and have a round external opening perforating the shell. They are described as Ostreoblabe perforans n. g. n. sp. Since they were probably oriented with their front part toward the inside of the shell, penetrating the pallial line, they were most likely parasites. In addition, long, meandering furrows sunk into the shells of pelecypods are described as Maeandropolydora decipiens n. g. n. sp. and M. sulcans n. g. n. sp. The real Polydora is not found in Pre-Tertiary strata and is probably not related genetically to Polydora like forms (Caulostrepsis) in Devonian strata.