342 COELENTERATA ANTHOZOA 



Grade A. Protoalcyonacea. 



This Grade includes those genera which, like many sea- 

 anemones, do not reproduce by continuous gemmation to form 

 colonies. 



Several genera have been described, and tliey have been 

 placed together in one family called the Haimeidae. 



Haimea fitnehris, M. Edwards, was found off the coast of 

 Algeria ; H. hyalina, Koren and Danielssen, in Norway ; Hartea 

 elegans, Wright, from the Irish coast ; Monoxenia darwinii, 

 Haeckel, from the Eed Sea, and a large new species found by 

 the " Siboga" Expedition in deep water off Ceram. All these 

 species, however, are very rare, and there is no satisfactory 

 evidence at present that they remain solitary throughout life. 



Grade B. Synalcyonacea. 



The sub-division of the Synalcyonacea into orders presents 

 many difficulties, and several different classifications have been 

 proposed. Only two orders of the five that are here recognised 

 are clearly defined, namely, the Coenothecalia, containing the 

 single living genus Heliopora, and the Pennatulacea or Sea-pens ; 

 the others are connected by so many genera of intermediate 

 characters that the determination of their limits is a matter of 

 no little difficulty. 



Order I. Stolonifera. 



These are colonial Alcyonaria springing from a membranous 

 or ribbon-like stolon fixed to a stone or some other foreign 

 object. The body-walls of the individual zooids may be free or 

 connected by a series of horizontal bars or platforms (auto- 

 thecalous) ; never continuously fused as they are in other orders 

 (coenothecalous). 



In the simplest form of this order, Sarcodictyon catcnatum 

 Forbes, the ribbon-like strands of the stolon meander over the 

 surface of stones, forming a red or yellow network, from the 

 upper surface of which the clear transparent anthocodiae of the 

 zooids protrude. When retracted the anthocodiae are drawn 

 down below the surface of the general coenenchym, and their 

 position is indicated by small cushion-like pads on the stolon. 



