Die Entwicklung der Larven bei der Bandwurmordnung Tetraphyllidea Braun 1900

The development of the larval stages of the Tetraphyllidean tapeworms is widely unknown. It is therefore tried to persue the cycle for the species Acanthobothrium coronatum (Rudolphi), a common tapeworm of the dogfish (Scylliorhinus canicula Cuv.) and some other sharks and skates. In 100 examined pilchards and anchovies numerous individuals of the so-called "Scolex pleuronectis Müller", a plerocerous Tetraphyllidean-larva, are found. The infected clupeids were fed to isolated sharks, which, finally opened, contained nothing but hundreds of the aboven nominated parasite. The way of the youngest stages is described. A coracid is not yet found but a small plerocercoid "Scolex" in copepodes. The development therefore seems to run about a first host, a copepode, which is eaten by the second, a teleostean pelagically living fish, which itself is devoured by a rapacious fish, mostly a shark, the definitive host, in other cases by another teleostean fish or a cephalopod, but these do nothing than "transport" the "Scolex" into the only definitive host, a shark or skate.