120 ACTINI-E OF AI.BATROj^S EXPLOHATIONS M'MrRUK^H. 



iiiu<iot' the ))resont contiiiy, ami to have had its liist oxi)(HUMit in ("u\ ier. 

 Kailior authors \vor«^ h'd astray by the siipposenl ve^vtabU- charactei' 

 of the corals and similar tonus, ami later, by attaehinji' too tjreat iui 

 portance to the presence or absence ot' a hard skeleton, whereby closely 

 related forms were widely separated. Thus Linne in the twelfth edi- 

 tion of his ''Systeina'' refened tlie ui'uus Acti>ii<t to the jMolhisca, the 

 remainiiiii' .Vctiiu)zoa beiui;' referred to two iiroups, the Lithophytt'S, 

 Avhich included thi' ^ladrepores, and Zoiiphytes, which, in addition to 

 the Aleyouaria, contained also sponges, Bryozoa, 8ertularia. and Pro 

 to/.o-A {Vorticelht). Pallas (IKiO) improved this arrangement slightly 

 by fusing' the Lithophytes and Zoiiphytes to a single group, but the 

 genus Actinid he referred, along with the l"ichini»dernis, to his grou[> 

 Centronia'. 



Cuvier by the foundation of the Kadiata. a group containing, it is 

 true, very heterogeneous members, did good service in bringing to- 

 gether more closely than previous authors the allied Anthozoa. The 

 third class of tlie Kadiata, the Acalephs, contained the genera Actinia 

 and ZoanthuH with which was associated LKcernaria, Avhile in the fourth 

 class, that of the Polypes, were gronj^ed together the rest of the An- 

 thozoa under the term ''Polypes corticaux a polypiers." The tribes of 

 this latter group with some of their principal genera are as follows: 



Tribe 1 Ceratophytes A;////>«///<'s, (rO)-(j(tiii<i. 



- Lithophytes^ /s/i", Madreponi, MiJIcpora. 



3 Polypes ui\geiirs:=re)ni<tttila, licnilhi, to wliich were added 

 Orbiilitcs. 



4 A\cyous=Alcifoiiiiini, S^XfUffia. 



It will be seen that the character of hardness or softness was given 

 considerable weight in the Cuvieriau system, leading to the association 

 in the same tribe of an Alcyonarian, a Hexacorallian, and a Tlydrozoon, 

 and similarly to the separation of various Alcyonarian genera, accord- 

 ing to their relative ctuisistency. The separation of the Actinians 

 from the Mollusca and their reference to the Acalephs is however a step 

 in advance, though their tru(^ relationships Avere unperceived. 



With eontemi)orar\' and succeeding systematists these two features 

 liehl firm ground. Lamarck (ISLS) though referring Zoauthun to the 

 Polyi)s with Hii(Ii((, Coripic, vtv.. returns to the classihcation of Actinia 

 with the Echinodcrms as advocated by Pallas, being followed in this re- 

 spect bj' Sell weigger (1820), w ho makes the i)reseni-e or absence of a hard 

 skeleton the criterion according to which tlie Zoiiphytes are referred to 

 the Z. motioliyla or Z. Jictcr<>lii/l((,\\n} former division containing Infusoria, 

 Kotifera, Znantli us, Tubularia^ and the Alcy imids. The reference of the 

 Actinians to one of the groups of the Polypes dates back to Lamou- 

 roux (ISlil), who still relying on the presence or absence of a skeleton 

 divides the Zoophytes into (1) Polypiers tiexibles, (2) Poly])iers pier- 

 reux. and (.i) Polypiers sarcoides. the last grou]) containing the Ac- 

 tinians together with the Alcyonids aiul the compound Ascidiaus. 



