.2 CERIANTHARIA. 



Genus 5. Botrucnidifer 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. in, b more or less distinct. 



Type: Botrucnidifer iiorvcgicus n. sp. 



Genus 6. Botruanthiis Mc. 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 w? 



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



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



Type: Bofntantlnis bcncdcvi (Torrey and Kleeberger). 

 Larval genera : Cerianthula E. van B e u e d e u. 



Henseiianilnila 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 Mc. Mxirrich (1910). As to the place assigned to the 

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

 where to insert the larval genera Apiacfis and Pcpoiiactis. For whilst van Beneden has described 

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

 which he ascribes to these genera. Should Mc. Murrich's larval forms really possess "acoutia", and 

 at the same time have to be referred to van Ben ed en's ^&r\exoL Apiacfis awA. Peponaciis, these genera 

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

 the range of possibility that Mc. Murrich's "acoutia" 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 Pachyccriantlins solitarius 

 and Crriaiithcopsis americamts] an appearance strongly suggestive of the "acoutia". 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 distingui.slied such a craspedoneme of the cnido-glandular tract 

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

 tlieui. I give expression to this su.spicion, 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 cxteiuled to embrace not only the typical formations in Arachwctis allmia. Arachnanthiis 

 oligopodiis and sarsi, but also the craspedonemes of Cerianthcopsis ameiicamn 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 Orimitheopsh 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 cra.spedion region. Compare also the acontium-like craspedonemes issuing from the region of the 

 ciUated tracts in Pachvcerianl litis maua. 



