208 ACTINOZOA. 



presenting this combination of characters has been 

 observed. The family Meridinidoe has, lastly, 

 been constituted for the reception of an equally 

 aberrant Astra^oid genus, Merulina, which clearly 

 points in the direction of the Fungidce, resembling 

 these corals in the perforate condition of its coral- 

 lum, though, as in the txMQ Astroeidoi^Tio synap- 

 ticulse occur. 



3. Order 2 : Alcyonaria. — The Alcyonaria, 

 with the exception of one genus, Hairrieia, which 

 may, however, yet prove to be an immature form, 

 are composite in structure; their polypes being 

 mutually connected by a coenosarc, through which 

 permeate prolongations of the somatic cavity of 

 each, forming a sort of canal system, whose several 

 parts freely communicate and are, therefore, rea- 

 dily distensible. 



Throughout the whole order the polypes exhibit 

 a very close agreement in structure, howsoever 

 much the coenosarc may vary. Each, when ex- 

 panded, displays a cylindrical, or somewhat octa- 

 gonal, tube, with delicate transparent walls, and 

 eight pinnate tentacula, whose form offers slight 

 though characteristic variations among the several 

 genera of the group. In some the polypes are 

 i-etractile into excavations which occur in the sub- 

 stance of the coenosarc, while in others such 

 excavations seem to be wanting. 



Alcyonium, the typical genus, presents, when 

 first dredged up, a sufficiently repulsive aspect, 

 suggestive of the vulgar names, " Cow's paps " and 

 " Dead-man's hand," sometimes conferred on it. 

 But, when placed in sea-water, the lobate fleshy 

 mass, distending its aquiferous system, is gradu- 



