284 PLUMULARIID^E. 



Genus AGLAOPHENIA, Lamouroux (in part). 



PLUMULARIA, Lamarck (in part). 

 AGLAOPHENIA, M'Crady. 



GENERIC CHARACTER. Shoots plumose, simple or branched, 

 rooted by a filiform stolon ; hydrothecce cup-shaped or tu- 

 bulous ; nematophores only developed in connexion with the 

 hydrotheca, two lateral and one anterior; gonothecce col- 

 lected in corbulce, or borne singly near the base of the pinna. 



FORBES long ago suggested the dismemberment of the 

 Lamarckian genus Plumularia. Johnston, taking the 

 hint, sketched a rearrangement in a note at the close of 

 his Hydroida, which very accurately represents the natu- 

 ral affinities, though he overlooked the character which 

 has the greatest value for the purposes of diagnosis. 

 More recently, Busk has proposed to divide Plumularia 

 into two generic groups, characterized by the disposition 

 of the nematophores and the presence or absence of a 

 corbula or protective case for the reproductive capsules. 

 Retaining the old designation for one of them, he has 

 suggested (but not published) the name Halicornaria for 

 the second. 



There can be no doubt that the Plumularia; (omitting P. 

 falcata, Lamk.) divide themselves into two very natural 

 groups, based on the special arrangement of the nemato- 

 phores. In one section these organs are appendages of 

 the hydrotheca only, and are disposed on a very definite 

 and constant plan around it ; in the others they are 

 distributed generally and profusely along the stem and 

 branches. With this cardinal distinction are associated 

 differences of habit and aspect which give a marked fades 

 to the two genera. 



