On the zoogeography and origin of the abyssal fauna in view of the knowledge of the porcellanasteridae

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By F. Jensenius MadsenZoological Museum. CopenhagenIntroductory remarks Historical steps in the exploration of the deep-sea faunaThe delimitation of the abyssal region The bathymetrical range of the Porcellanasteridae The mode of life of the Porcellanasteridae The geological age of the Porcellanasteridae The interrelationships of the porcellanasterid generaThe geological age of the deep-seaLife conditions in the ancient and in the recent deep-sea The theoretical composition of the deep-sea fauna The geological age of the recent deep-sea faunaThe alleged antiquity The Mesozoic and Early Caenozoic elementsThe Late Caenozoic elementsThe factors deciding the vertical zonation of the deep-sea faunaSome characteristics of deep-sea animals The horizontal distribution of the abyssal fauna The cosmopolitanismSome cosmopolitan species EKMAN'Sco nsiderations on a possible cosmopolitanism of the abyssal fauna The main subdivision of the lower abyssal fauna The "guests" in the abyssal region Commentary on N.G.Vinogradovav'iSe w on the abyssal zoogeography Possible explanations for an Atlanto-Indian and a Pacific (East Pacific) abyssalfauna element respectively The alleged endemism in the trench faunas The distribution of the abyssal fauna in relation to the condition of the bottomThe possible fluctuations in the abyssal populations