CERIANTHARIA. 



Genus 5. Botritcnidifer nov. gen. 



Botrucnidiferidae with botrucnidae in the most aboral part both of protocnemes 2, protocnemes 

 3 and of macro- and microcnemes (brachycnemes). Metacnemes and protocnemes 2 with region of 

 the cnido-glandular tract. Protocnemes 2 long, fertile. Arrangement of metacnemes in each quartette 

 M, B, m, b more or less distinct. 



Type: Botrucnidifcr norvegicus n. sp. 

 Genus 6. Botruanthus Me. Murrich. 



Botrucnidiferidae with cnidorages (botrucnidae?) dispersed over the craspedonemes and bunches 

 irregularly. The region of the cnido-glandular tract on protocnemes 2 and metacnemes M and ///? 

 Protocnemes 2 (short?) rather long, (sterile?). Arrangement of metacnemes in each quartette M, b, m, B, 

 more or less distinct. (Diagnosis on the basis of Torrey and Kleeberger's description). 



Type: Botruanthus benedcni (Torrey. and Kleeberger). 

 Larval genera: Ccrianthula E. van Beneden. 



Hensenanthula E. van Beneden. 

 Calpanthula E. van Beneden. 



As I have not treated the larval forms thoroughly in this work, I refer for further details to 

 the works of E. van Beneden (1898) and Me. Murrich (1910). As to the place assigned to the 

 larval forms, it does not differ much from Me. Murrich's. Still it seems to me rather doubtful 

 where to insert the larval genera Apiactis and Pcponactis. For whilst van Benedeii has described 

 these larval forms as not possessing "acontia", Me. Murrich has found these in some new species 

 which he ascribes to these genera. Should Me. Mnrrich's larval forms really possess "acontia", and 

 at the same time have to be referred to van Beneden's genera Apiactis and Pcponactis, these genera 

 must then be classed under the family Acontiferidae and not under Cerianthidae. But it is not beyond 

 the range of possibility that Me. Murrich's "acontia" are nothing more than thread-like cnido-glan- 

 dular tracts or slightly differentiated craspedonemes of the craspedion region, which, as I shew in this 

 work, may have, as far as exterior goes, in certain Ceriantharia (for example in Pachyccrianthns solitarius 

 and Ccriantheopsis americanus] an appearance strongly suggestive of the "acontia". To settle this 

 point however close study of the type specimens would be required. It is possible besides that van 

 Beneden also has not always clearly distinguished such a craspedoneme of the cnido-glandular tract 

 or of the craspedion from "acontia" but has described as "acontia" J ) all formations which resemble 

 them. I give expression to this suspicion, because van Beneden, as I believe I have shewn (com- 

 pare section 4), did not have a clear conception of the structure of the "acontia". In that case either 

 the whole or a part of the larval genera of Ceriantharia must undergo revision. 



*) If the term "acontia" is extended to embrace not only the typical formations in Arachnactis alln'da, Arachimnthus 

 oligopodiis and sarsi, but also the craspedonemes of Ceriantheopsis americanus issuing from certain craspedia, which in their out- 

 ward conformation, though not in their inner structure suggest the "acontia", then of course it will be necessary that the 

 whole genus Cerianthcopsis should be transferred to the family Acontiferidae. By "acontia" would then be under- 

 stood every threadlike organ issuing from the craspedion that is more or less differentiated in structure from the 

 craspedion. For the present however I believe it will be more advisable to distinguish the "acontia" from the less differentiated 

 craspedonemes of the craspedion region. Compare also the acontium-like craspedonemes issuing from the region of the 

 ciliated tracts in Pachvcerianthus inaua. 



