180 Mr. E. Forbes on the British Actiniadae. 



X X. — On flic British Actiniadae. By Edward Forbes, Esq. 



[With a Plate] 



I. Such Actiniadae or simple soft Ilelianthoid Polypes as are 

 found in the seas of Britain may be arranged under five ge- 

 nera, namely, hucernaria (Muller), Anthea (Johnston), Acti- 

 nia (Linnaeus), and two which I propose to constitute under 

 the nanus of Adamsia and Iluanthos, the first for the recep- 

 tion of the Actinia maculata of Pennant, the second for a new 

 animal procured on the west coast of Scotland during last 

 summer. As the Actiniadae conduct us very naturally from 

 the Zoophytes to the Actinodermata, we should expect to find 

 some two genera more closely linking the approaching fami- 

 lies of each great order than the other genera composing these 

 families ; such seem to me to be found among the Zoophytes 

 in Lucernaria and among the Actinodermata in Vorticetla, 

 which I regard as a pedunculated Actinodermatous animal. 

 By the laws of analogy such an animal should exist, corre- 

 sponding with the Crinoid Starfishes among the Echinoder- 

 mata, which in like manner connect that order with the Zoo- 

 phytes through the suborder Ascidioidea on the part of the 

 latter. 



As there can be but one analogy in the tribe of the importance 

 assumed by Lucernaria, the other genera are representatives 

 of minor groups, Anthea standing by itself as the typical ge- 

 nus of the Actiniadae. Actinia we may regard as a soft Ca- 

 ryophyllia, Ttuanthos as a soft Turbinotia, and Adamsia pro- 

 bably as an encrusting Zoophyte. 



The points of generic character among the Actiniadae ap- 

 pear to be, (1st,) the general form ; (2nd,) the mode of attach- 

 ment ; and (3rd,) the arrangement and retractility of the ten- 

 tacula. 



The sources of primary specific character are in Lucerna- 

 ria, (1st,) the mode of attachment ; (2nd,) the number and ar- 

 rangement of tentacula ; and (3rd,) the presence or absence of 

 intermediate marginal tubercles (eyes?). 



In Anthea, (1.) the characters of the body ; (2.) the length ; 

 and (3.) the structure of the tentacula. 



