^"iH'.n"] PROCKEI)IN(;S OK TIIF. NATIONAL MUSKIIM. 141 



within it not only licxanicious forms, but iilso octaiiieroiis and decani- 

 erons Actinians, in otlicr words, I fuse, witli tlio <nij;iiial riexa(;tinia'- 

 Hcrtwiju's tribe l*ara.(5tinia', wlii<;b is alt().n('tli('r artilicial and unneces- 

 sary. My reasons ibr tliisopinion iKivebccn liiNcn at Icn^tli clsewliere 

 and need not be rei>eated ('SD, '01). 



Order A('TININ^^], AiulrcH. 



llexac.tinia' in wliicli tlic tcntacies arc arranged in <'y<*l<'^^, only a sin- 

 gle tentacle conmiunicating with each endoco'l. 



Kainily TI A L('AM rn>.K. 



Actinina' Avithasniall nninbcrol mesenteries, six, ten, or twelve jtairs 

 beinjif all that are i)resent ; lonj;itn(linal jnuschs i)eiinons narrow, but 

 strcmj:?; no S])ecial sphinetin muscle; conchula present or al)sent; base 

 usually rounded and v<'si<'ulai'. 



lnhisnionoj;raph, An<lr<'S ('s;}) divided tlielaniily llyanthida', wliich 

 had been previously limited by the exchision of the ( Perianth ea', and 

 Edwai'dsiie, into three distinct families, or, as he t<'rmed them, sub- 

 families. Oneof these, the 1 Ialcain[)ida',c(Hit ain<'d t-iiegenns Ihdcainpa, 

 the llyanthida' incbided only t he <>'enus //y^^/////^v, while ibr those forms 

 which ])oss(^ssed a conchnla the family Siphonact inida' was established. 



A nioi'e recent ant lior, Ihnhlon ('S9), seems to regard this last fam- 

 ily with uncertainty. At all events he removes from it and associates 

 with the llalcanii)ida' the genus /VvfcA/Vr, recognizing, howevei, the 

 the i»ossil)le necessity Ibi' tlu'- establishment of a separate family Ibr it. 



The nn(5ertainties which interfere with the delimitation of the family 

 ITah^ampidai are mainly two. An; forms which ])ossess a, (M)nchula to 

 be associated with others which do not have this strncture, but whose 

 mesenterial arrangcMnent is similar? And are decaniei-ous to be asso- 

 ciated with hexamerous Ibrmsl? 1 believe that both these cpu'stions 

 should be answered alfirmatively. l^he forms belonging ta the family 

 SiphoiKM-tiniila^, so far as tiny are known, agree in certain important 

 features, viz, in the usiuil absencre of an adhercuit base, the absence of 

 a s])hincter, the small nund)er of mesenteries, and the strong though 

 narrow longitndinal mnscles, with the niend)ers of the genns Ihihuiinpd, 

 and ditfer from them only in the possession of a conchnla, a, stiucture 

 ofpr<)l)ably comi>aratively little morphological inip(»rlance. As regards 

 the arrangement of t he mesenteries, even if we separaie t he tbrms with 

 a <'<mchula IVom those witliout it, it will be necessary to associate 

 together hexamerons and decainerous species, nnless we wish tomnlti- 

 ply families beyond convenience ;ind necessity. Il((l(<(mpa ciKiroiiiildfa, 

 et(;., a re hexamerons, and II .proihicUi is decamerons among the 1 lalcam])- 

 i(he; and among conchnhi-bearing forms I'cftcliia /ia.v/,af«isdecamei'ons, 

 while liirulium pardslticum is h(^xa-merous, possessing twelve pairs of 

 jnesenteries. 



