LITERATUEE OF TIIE SUB-KINGDOM CCELENTEEAI \. J 27 



The class Coralliaires Milne Edwards dhidos into two equal sec- 

 lions, in one of whirl), Cnidaiivs, are placed all the Actiuoid poJ 

 (Zoantharia and Alcyonaria), while the seror.d di\ ision, Podactinaircs, 

 includes but the genns Lucernaria of older authors (tamilv Lticer- 

 nariad;e of Johnston). The true position of this curious form and 

 its immediate allies is a question of linn-h interest to the swirmatie 

 zoologist, imolving as it does, to a certain extent, the determination 

 of those Urst principles which should guide him in the recognition of 

 natural groups among the Cielentera.ta, "Jihrcnborg, l)a-.:i. Juh; 

 and the greater number of those who, since the time of Cuvier. ha\e 

 written on Lucernaria^ associate this genus with the Aciinoid 

 polypes, not far from Actinia itself. But a grown ■■_■; idea of is dis- 

 similarity in structure to the true Polypes has of late jri ars I 

 impressed on the minds of several zoologists. Thus, in lSoO, 1 ' Miiae 

 Edwards referred it to an order equivalent to Zoantharia or Alcyena riii, 

 and in 1857,4 s as has been shown, he regarded it, from a systematic 

 point of view, as on a par with these two orders taken collectively ; 

 so that, while placing it in one class with the polypes proper, ho, 

 nevertheless, removed it to the greatest possible distance from these 

 organisms, consistent with such an estimate of its affinities. But 

 others, at a much earlier date, had gone still further. Lamarck, in 

 1816, 46 had hinted at the relationship of Lucernaria to the Disco- 

 phora ; and twenty-four years later, in one of the notes appended to 

 the posthumous edition of his principal Work, a similar opinion is 

 still more explicitly urged by Dujardin. 47 Greater definiteness was 

 soon after given to this view of the nature of Lucernaria by Frey and 

 Leuckart, 48 who, in the same treatise wherein they first called attention 

 to the existence of the sub-kingdom Ccelenterata, instituted a direct 

 comparison between the organization of Lucernaria and Pclagia, 

 tending to show that the four-lipped alimentary proboscis of the 

 former is truly the homologue of the prehensile nutrient organ de- 

 pending from the swimming disc of the latter ; this disc, moreover, 

 which bears round its margin a number of long slender tentacles, 

 corresponding in its structural relations to the cup-like body-wall of 

 Lucernaria, which, though usually fixed, is, at times, capable of per- 

 forming the function of natation. In the following year, the 

 systematic position of Lucernaria was reconsidered by Leuckart, who 

 still, however, hesitated to remove it from the class of Polypi, though, 



43 In the second edition of the licgnc Animai, Luccrnaria\% placed after Actinia 

 and Zoanthus; in the first edition (1817) a nearer view is taken of its relationship 

 to the Discophora. 



44 Edwards and Ilainie, in Monograph of British Fossil Corals, Introduction, 

 p. lxxxv. 



45 Op. s. cit. Tom. I. p. 94. 



46 " Lcs luccvnaires commcnccnt a donncr une idee des mcdttsaires." — Hist. Nat. 

 des An. sans Vertcb , Tom. II., p. 473. 



47 Second cd. of Lamarck's Hist. Nat. des An. Sflbs Vertcb , Tom. 3, p. 5S. 

 43 Beitrage, p. 10, and PL I. figs. 3 and 4. 



