MR. GOSSE ON PEACHIA HASTATA- 275 



,., ( Anterior extremity normal Ilyanthus. 



\ Monotrematous ] ... , 

 Non-adherent < *■ Anterior extremity forming a retractile column Edwardsia. 



(_ Ditrematous Peachia . 



If we take Sagartia as the typical genus, which its superior populousness, and the 

 perfection of its armature entitle it to be considered, we may trace, as from a central 

 point, some of the relations of the Actiniadce, inter se, as well as with other forms. 



Adamsia comes very close to Sagartia, possessing the power of emitting filaments in 

 high perfection : probably the point of union between these genera will be S. parasitica ; 

 which, like Adamsia palliata, attaches itself to shells in which Paguri dwell ; and which 

 is pre-eminent in its genus for the abundance and the tenacity of its filaments. The 

 passage from Sagartia to Bunodes is perhaps through S. Dianthus and B. clavata; 

 the disk of the latter being very expansive, with the tentacles situated at its margin. 

 S. Bellis, in its power of assuming a saucer-like form for its thin expanded disk, to which 

 the narrow body serves as a foot-stalk, shows also a remote approach to Lucernaria, in 

 which this figure is permanent. 



Lucernaria exhibits a beautiful link of connexion between the Actinoderm and the 

 Arachnoderm forms of Radiata. The Oceania turrita has its umbrella produced into a 

 long moveable spire, which looks exactly like a foot-stalk, by which it had been attached 

 when in a polype condition; while in Bougainvillcea we get the numerous tentacula 

 gathered into groups. The mobile, four-lobed mouth of Lucernaria closely resembles 

 the peduncle of a Medusa. 



There is a curious analogy (I fear it is nothing more) between Lucernaria and the 

 genus Floscularia among the Rotifera : both are attached by a slender pedicel ; both 

 have a flower-like disk, jutting out into angles, which are beset with a multitude of fila- 

 ments (tentacles in the one case, setiform cilia in the other) that radiate in all directions. 



The tender and soft-bodied little Sagartia Candida and S. rosea seem to lead off to 

 Corynactis Allmanni, though the points of resemblance are rather general than special. 

 But this latter genus passes into Capnea, by a remarkable species described by Mr. W. 

 Thompson of Weymouth, in the Zoological Transactions for 1853, under the name of 

 Corynactis heterocera, and which I had an opportunity of examining while alive. Pro- 

 fessor Forbes has observed the close affinity of his Capnea sanguinea to the Zoanthadce, 

 and the transition which the latter exhibit to the creeping and budding Hydroid polypes 

 is sufficiently apparent. Corynactis, in its capitate tentacles, shows also a relation to 

 Cyathus Smithii, among the coralligenous Anthozoa ; while the simply-conical form of 

 these organs in Balanophyllia regia agrees with Actinia, &c. 



The transition from Sagartia to Actinia proper, I do not know how to trace, except 

 by characters common to the whole group. The soft-bodied species of the former genus, 

 which do not possess sucking glands, as Candida, venusta and nivea, are however cer- 

 tainly more closely allied to the smooth-skinned A. Mesembryanthemum than such coarse 

 species as S. Bellis, parasitica, &c, and this is all I can say. 



I think, however, that Actinia makes a decided approach to Lucernaria, in the capsu- 

 liferous spherules of the margin ; for the oval appendages which are placed on the edge 

 of the disk, in the latter genus, alternating with the groups of tentacles, are, I doubt not, 

 consimilar in structure and function to those spherules. 



vol. xxi. 2 o 



