122 APTTNT.i: OF ALBATKOSS KXPLOKATIONS M'ArrRUTrH. 



E('((K'in|):c and I'^iidociirpa' is louiulcd on tlic identical cliaracttM-istic 

 wliicii IJapp cliosc, tlioiiiili llic more recent. an( liors deline more accu- 

 rately the place ol" origin ol" tlie reprodiictiN'e elements in tiie terms of 

 tlio iiorm-layers, sinictiires nnknown to IJapp. 



rnfortnnately, (he systematists who immediately succeeded llapp did 

 not achance the position he had occupied, i )e rilaiiixille's association 

 of the Actinians with the Madrei)ores has already been noticed, a hapi)y 

 exception to the complicatt'd confusion into which he falls as to other 

 j^roups. On the whole, how('\'er, his classilicat ion nnisl be considered 

 an advance as compariMl witli that of I'^direnbei'^' (".'>!), who falls back 

 to the old consistence system, thon^h a\()idin,i;- he lUainvillei's per]»et- 

 nation of the eailier ndsconceplion of (he Uryozoa as allied to the Zoii- 

 ])hytes, To I'^hienberi; we owe the substitution of the term Antho/oa 

 for that of Z()o])hyta, employed by earlier wiiteis, and (his "ciiculus" 

 he divides into two orders whose limitations may be seen from tin' fol- 

 lowing syin>psis: 



Ciii'uhis I. — Aiitlio/.o.-i. 

 Ordo I.— Z(>tic()i;illi;i. 



Tiilnis l.-^Zo(')r,oi':illi;i ]t()ly;ictiiii;i ( Actiiiiniis, Zo.iutlKuis, iiiid l'iiii>ji(l;i'). 

 'I'liluis 11. — Zi»(ic'(ir:illi;i (tctact iiiia. (Xciii.is, Tiihiinnids, Alcynnids, and 



I'omiiitulitls). 

 Trildis III. — Z()(l('()nillia olinacl inia ( Ifvdroids). 

 Ord.. II. I'liN tucdiallia. 



Iriliiis 1\'. riiyldcoraUia jiolyact iiiia ( ( >ciiliiii(ls and j\stra'ids). 

 'rrihiis \'. — Pliytotovallia dodceaclhiia (.Madrepoios and MilU'poros). 

 'I'ril)ns \ 1. — I'liylocoialliii octacliniai (Coralliiini, Isids, and (iornonid.s). 

 'I"ril>iis \ 11.^ I'liyl.M-orallia .diua.'linia ( .///«/;<>;•<(). 



It will be seen from the abo\e thai the Zo(>coiallia inchnU's all those 

 forms w hicli are destitute of a hard skeleton, or which, like l''uni;ia, 

 possessinii' a coralliim are not lixed, w hile the riiytoeorallia embraces 

 the forms |»rovided with a hard skeU^ton, bein;:; at the sanu' time 

 tixed. Such a classilication necessarily se])arates closely allied forms, 

 as, for instance, the I'^iiniiida' from the other 1 lexacoiallia. and the 

 I'ennatulids from the (Joriit)nids. The j^roup .\ntho/oa as conceived 

 by l''hrenbei;n differs from the modern concei)tion of the .urouj) in in- 

 cludinju the llydroids and llydioeorallina', in w hieh respect Khrenberg 

 falls far behind Kapp, and in exeliuliui; the .Vntipatharia wdiieh are in 

 this system referred to tlu' llryo/oa. In one ]>articular, however, 

 I'ihrenberg snri)asses his predecessors, with the exception of IJapp, and 

 that is ill employinii' for his secondary uroups characteis which belong 

 to the living animals. The lunnbei' of the tentacles is a feature which 

 within certain limits has been found to be associated with the features 

 which nuirk out the various groups as now recognized. 



The association ol the varit)ns eight-tentacled forms into a single 

 grou]> was one of the important steps which now followed. .Vccording 

 to a statement made by Dana cKIa) this was tirst dout' by .Milne Ed- 



