1848.] LONSDALE ON FOSSIL ZOOPHYTES. 75 



centre of a terminal branch, where the interspaces also are generally 

 very narrow ; but in the part equivalent to the outer zone of the 

 low^er greensand fossil, and at a considerable distance from the upper 

 extremity of the branch, small abdominal cavities sometimes ajjpear. 

 In a specimen believed to be the Sid. scabra of De Blainville*, the 

 young receptacle was produced by the plates of the interspace ar- 

 ranging themselves so as to form an imperfect star ; while in Focil- 

 lopora damicor?iisf, which has only rudiments of lamellae, the inci- 

 pient cavity was a small irregular hole ; in Choristopetalum impai', 

 on the contrary, the additions were apparently made by the conversion 

 of a cell into a visceral hollow\ 



It remains to hazard an opinion relative to the systematic position 

 of the fossil. Little doubt can be entertained, that it should be as- 

 signed to the class Anthozoa ; and its curious, complicated struc- 

 tures supply additional reasons why the term polype should not be 

 restricted to the tentaculated mouth and digestive organs ; but ex- 

 tended, if for convenience sake it be retained, to the w^hole of the 

 animal, and anatomical terms applied to the individual structures :J;. 

 In attempting however to define more precisely the position of the 

 extinct genus, the absence of lamellae or all representatives of them 

 presents a great difficulty. Among existing stony Anthozoa, Tubi- 

 pora is the only genus known to the com])iler of these memoranda 

 which is equally deficient ; but that zoophyte is furnished with eight 

 pennated tentacula, and on that account is placed by Ehrenberg 

 among the eight radiated or lamellated coral animals (Beitriige, Syst. 

 Table). It would be clearly altogether incorrect to assume, that the 

 fossil under examination possessed, when alive, eight similar tenta- 

 cula ; and much investigation is necessary before a positive agree- 

 ment between the number of those appendages and that of the lamellce 

 can be admitted. Lesueur§ divided the corals, referred by him to 

 Astrsea, into tw^o groups, one provided with tentacula, the other de- 

 stitute of them ; notwithstanding all the species are many-lamellated ; 

 and he describes Agaricia purpurea as without apparent tentacula 

 {op. cit. p. 2/6). Ehrenberg states his whole family, Milleporinay 

 wants that structure {op. cit. p. 122), but is furnished throughout 

 with six to twelve obsolete lamellae ; Mr. Dana, how^ever, alludes to its 

 existence in the genus Pocillopora, as well as in a new species ofSeria- 

 topora\\. Explayiaria Hemprichii^^ Pavonia cactus^* , Tridacophyl- 

 lia lactucaff, and the small genus EchinoporaXXi ^^^ described as 

 wanting tentacula ; but they are all lamellated. Some of these state- 

 ments are possibly founded on animals which, at the time of obser- 



* Man. d'Actinol. p. 384 ; Atlas, pi. 60. fig. 2. 



t Lamk. ii. p. 442 ; Esper's Pflanzentliiere, Madrep. tab. 46 «& 46 a. 



X Consult Dr. Grant's Memoir on Flustrge, Edin. New Phil. Jonrn., No. 5, p. 116, 

 1827 ; also M. Milne-Edvvards's Memoir on Recent Escharae, p. 24, Ann. des Sc. 

 Nat., 2nd series, Zool., tome vi. 1836, or Reeherches sur les Polypes, &c. 



§ Mem. du Museum, tome vi. pp. 285, 286, &c. 



II Exploring Expedition, Zoophytes, pp. 523, 521. Ser. hysirbc, 1846. 



^ Ehrenberg, Beitrage, p. 82. ** Ibid. p. 105. 



ft De Blainville, Man. d'Actinologie, p. 362. 



XX Consult Mr. Dana, Expl. Exped. p. 277-278. 



