What is "goniocidaris hystrix"

Piper \Pip"er\, n.

1. (Mus.) One who plays on a pipe, or the like, esp. on a bagpipe. ``The hereditary piper and his sons.''
   --Macaulay.

2. (Zo["o]l.)

   1. A common European gurnard ( Trigla lyra), having a large head, with prominent nasal projection, and with large, sharp, opercular spines.

   2. A sea urchin ( Goniocidaris hystrix) having very long spines, native of both the American and European coasts.

      To pay the piper, to bear the cost, expense, or trouble.