CERIANTHARIA. 



The first division of adult Ceriantharia on an anatomical basis has been recently (1910) made 

 by Me. Murrich in his work on the Ceriantharia of the Siboga Expedition, in which he takes account 

 of larval as well as of full grown forms. 



Me. Murrich's classification of Ceriantharia (1910) is of the following nature. 



i Suborder Acontiferae van Beneden. 



Ceriantharia in which the second or fourth protocnemes, or in some cases both these mesen- 

 teries, are provided with acontia at least during the early stages of development. The deuterocnemic 

 marginal tentacles appear in the same order as the mesenteries to which they correspond. 



i. Family Ccrianthidac. 



Acontiferae in which the second couple of protocnemes are the telocnemes. The succeeding 

 protocnemes are represented by a brachycnemic couple, usually sterile, and by a macrocnemic couple. 

 Acontia are borne in larval stages upon the telocnemes and in some cases also upon the macrocnemic 

 protocnemes. 



Genera: Cerianthus, Apiactis 1 }, Solasteractis, Peponactis. 



Genus Cerianthus D e 1 1 e C h i a j e. 



Acontiferae living imbedded in mud or sand and provided with a sheath consisting of felted 

 nematocysts and mucus: mesenteries and tentacles usually numerous, so that the quartette arrangement 

 of the deuterocnemes is distinct. 



Type: Cerianthus incnibranaccus. 



2. Family Arachnactidae. 



Acontiferae in which the fourth couple of protocnemes, counting from the mid-ventral line, 

 form the telocnemes. The second and third couples of protocnemes are sterile. Acontia are borne in 

 larval stages by the fourth protocuemes, but never by the second. 

 Genera: Pachyccrianthus, Arachnactis, Dactylactis, Ovactis. 



Genus Pachyccrianthus Roule. 



Arachnactidae living imbedded in mud or sand and provided with a sheath composed of felted 

 nematocysts and foreign substances. Mesenteries and tentacles usually numerous and the quartette 

 arrangement of the deuterocnemes distinct. 



Type: Pachyccrianthus bcnedeni Roule. 

 Suborder 2. Botrucnidif erae (van Beneden). 



Genera: Botruanthus nov. gen. (Type Botruanthus benedeni (Torrey and Kleeberger), Ccri- 

 anthula, Hensenanthula, Calpanthula. 



Though like Me. Murrich I am fully conscious that we cannot at present make a satis- 

 factory division of the Ceriantharia, I am still of opinion that by the help of the accounts here given 

 of the morphology of the Ceriantharia, Me. Murrich's scheme may be considerably improved upon 

 in various points. But before I pass on to my own suggestion for the grouping of the Ceriantharia, 

 it might be well to look carefully into Me. Murrich's division. This shews that Me. Murrich 

 retains van Beneden's division of the Cerianthidae into 2 groups Acontiferae and Botrucnidiferae. 



') As the scope of my work includes principally adult forms, I do not insert here the diagnosis of larval genera. 



