APPENDIX TO CHAPTER XIV 



221 



61. Hydroids present ; medusae without free 



auditory clubs. 



Ci. Hydrflid stocks, with calcareous ex- 

 ternal skeleton ; no free medusse . Hydrocorallidce 

 c 2 . Hydroid heads never enclosed in cuticu- 

 lar cup ; medusse, if free, without 

 marginal vesicles ; gonads on manu- 



brium Tubularidw 



c 3 . Hydroid heads enclosed in calyx ; me- 

 dusae, if free, with gonads on radial 



canals Campanularidce 



b- 2 . Hydroids absent ; medusse with free-stand- 

 ing auditory clubs. 



ci. Gonads on radial canals . . . Trachomedusce 

 c 2 . Gonads on manubrium . . . Narcomedusce 



