Flozverlikc Forms and Fantasies 177 



name was first applied. But now, since our knowledge 

 of these animals has been vastly extendetl, a (juitc 

 numerous group of individuals has been included among 

 them which have no resemblance to a feather. For in- 

 stance, there is one {Antenniilaria antennina) which 

 often appears in my tide pool, that is decidedly weed- 

 like; it grows in dense clusters of sparsely branched up- 

 right stems to a height of eight or more inches, and is 

 by no means prepossessing. However, among those 

 forms which do bear out their characteristic name, are 

 the most beautiful of all fixed hydroids. Such is the sea 

 plume {Aglaophemia struthioides) ^ a species found on 

 the Pacific coast. It has a striking likeness to a min- 

 iature ostrich plume, and the rich, colorful tones of 

 some individuals make them even more attractive than 

 the object for which they are named. This hydroid, 

 like many other plumularians, has the zooid cups ar- 

 ranged only on one side of their supporting branch. 

 The cups are without pedicels, or stems. 



But there is one thing in which plumularians agree, 

 and it is the distinctive feature that now identifies all 

 members of the group regardless of their superficial 

 aspects. This is their stinging organs known as 

 nematophores. Whereas, in the other fixed hydroids 

 that we have considered, the tentacles of the hydranth 

 are the only organs bearing stinging cells, in these crea- 

 tures the nematophores are additional members in- 

 vested with these deadly darts. These are bodies of 

 sundry shapes, the external shell being generally tubular 

 or trumpet-shaped, containing a single tentacular finger 

 capable of great extension. They are variously situated 

 along the internodes and sometimes on the sides of the 



