llie polyps, and they undoubtedly possess many features of 

 general resemblance to the Avell-known fresh-water polyp 

 Ilydia. A critical examination of the anatomical 

 structure of the Alcyonaiian, however, proves that the 

 name " polyp is misapplied in this case, for the bodies 

 referred to only correspond with a part of the polyp of 

 the Hydia, iuimeh% the free end with the crown of 

 tentacles, the greater part of the fixed or proximal end 

 of the Alcyonarian polyp being buried in the massive 

 substance of the coral. We have, in other words, two 

 parts in the body of the Alcyonarian polyp, — (i.) a pai( 

 which is free and can be retracted or expanded at will, 

 and (ii.) a part which is attached and hrmly welded to the 

 corresponding parts of neighbouring polyps. 



^Vitll this explanation of the general siructure tlie 

 icadfM- is pre})ared to understand the critical or diagnostic 

 teatnrcs 1)\ which a given specimen may or may not be 

 referred to the Order Alcyonaria. 



The Alcyonaria are Coeleiiterata wliieli (with 

 one or t\v(j rare exeeptioiis) I'onii colonial 

 organisations by budding. The individual polyps 

 composing the colony are provided with eight 

 tentacles at their free extremity, and each of these 

 tentacles is provided with tv\^o or more rows of 

 papilhform processes called pinnules, giving the 

 tentacles a feathered or pinnate forni. 



The form which the Alcyonarian colony takes varies 

 immensely in the dilferent families into which the Order 

 is divided ; some being encrusting plates, some lobular in 

 form, some shrubby, some mushroom shaped, and so on, 

 but a detailed description of these forms would take me 

 beyond the scope of this memoir. The important point to 

 note here, however, is that although there is a remarkable 



