CONTENTS. 



Ceriantharia. 



Pa K e 



Introduction i 



Literature and survey of the northern Ceriantharia 3 



Description of species 5 



Family Cerianthidae. Pachycerianthus multiplicatus n. sp 5 



Cerianthus lloydii Gosse 1 1 



vogti Dan 18 



Ceriantheopsis (n. gen. I americanus (Verr.) 22 



Family Acontiferidae. Arachnanthus in. gen.) sarsi n. sp 27 



Family Botrucnidiferidae. Botrucnidifer (n. gen.) norvegicus n, sp 30 



Larval forms. Arachnactis albida Sars 34 



Classification of the Ceriantharia 37 



(Corianthas valdiviae n. sp.) 44 



Morphology 48 



Arrangement of tentacles 48 



Stomatodaeum, siphonoglyph, hyposulcus, hemisulci 49 



Arrangement of mesenteries 50 



Mesenterial musculature 53 



Orientation of body 54 



Mesenterial filaments 59 



Acontia 68 



Botrucnidae 72 



Bibliography 77 



