ACTIN0Z0A. 199 



tto 



iry 

 ;oa 



ies 



of 



i so 



ars 



ace 

 or 



c ^l tionally larger than in most of the Actinidce 



red proper. The base is either rounded or bluntly 



tapering, and, in certain genera, becomes at times 

 much distended, as in Saccanthus or Edwardsia. 

 In some the base is furnished with a central 

 perforation : in others this appears to be wanting. 

 In Peachia the oral region is singularly modified ; 

 the tubercles of its single groove uniting to form 

 a tube, the expanded summit of which, ' conchula ' 

 ind I of Mr. (xosse, presents a more or less thickened, 

 his everted edge, cleft into a variable number of lobes. 



$1 The polypes of the Zoanthidce and true coral- 



»of lio-enous Zoantharia, save in characters merely 



the I generic, resemble those of the Actinidce. Their 

 be average size is, perhaps, smaller, though the Ac- 



tinia Paumotensis of the Pacific, whose expanded 

 disc measures a full foot in diameter, is, in this 

 respect, certainly exceeded by large specimens of 

 Fungia. This genus presents a widely extended, 

 circular or elliptic disc, destitute of the usual 

 folding margin, and blending, by insensible de- 

 grees, with the shallow, ill-defined column, over 

 the radiating septa of which the tensely stretched 

 soft parts converge towards the prominent, central 

 mouth. Such a simple form contrasts strikingly 

 with Meandrina and those allied genera in which 

 ieir the several polypes produced by fission fuse to- 



ove I gether into a convoluted linear track, with tentacles 

 ,ral arising from its opposite sides. 



eed Of these appendages and their variations, a 



brief notice seems here required. In Anthea 

 Aid (—Anemonia) they are long and slender; in 



Fungia and Discosoma, reduced to mere warts 

 or papillae; in Capnea, very short, resembling 



oblong tubercles ; while in Arachnactis, the outer 



Bi- 



as 

 or- 



O 4 





