primaries in th<- Zoanthactiniaria, bul while in the Ceriantharia tl ondary mesenteries 



always retain the coupled condition, in the Zoanthactiniaria they form pairs with tli<- lateral 

 primary mesent an hexamerous symmetry, with the mesenteries in six pairs, being tlms 



produced. Finally in th<- Zoanthactiniaria a tertiary group of mesenteries is added, these mesenteries, 

 as a ruif. being developed in pairs. 



h seems convenient to have distinguishing terms for these three groups of mesenteries. 

 ied the use of the term protocnenv - for the mesenteries constituting 

 the si\ primary j >.iirs of the Zoanthactiniaria, that is to say for th<- primary and secondary 

 :nteries recognized above, and for the additional coupled mesenteries of the Cerian- 

 tharia and for the paired «mes of the Zoanthactiniaria hc employed the term metacnemes. This 

 nomenclature is open to the objection that it disregards the significance of the eight mesenteried 

 stadition found in the Alcyonaria and the Zoanthactiniarian larvse and almost implies that this 

 condition is a derivative from a six-paired one; further it makes the secondary coupled mesenteries 

 of the Ceriantharia equivalent to the paired tertiaries of the Zoanthactiniaria. I would limit the 

 term protocneim ^ to the eight primary coupled mesenteries. and for the secondary coupled 

 1 would suggest the term deuterocnemes, while for the mesenteries which succeed 

 these in the Zoanthactiniaria and which usually develope in pairs I propose the term zygocnemes. 

 I i rden's term metacnemes might be employed either for these or for the deuterocnenn-s, but 

 to avoid any confusion that might result from its application in a new sense it has seemed 

 preferable to discard it. 



