INDEX TO THE CTENOPHORA 



Peron, 2 

 Pilidiuni, 19 

 Planariaus, 16 

 Plati/denea, 22 

 Platylielminthes, 12, 18, 19 

 Pleurohrachia, 2, 20 

 Pleurobrachiidae, 20 

 polar fields, 5 

 Polyclada, 12, 16, 19 

 pseudoblastopore, 10 



Quoy, 2 



ribs, 2, 17 



Riches, T. H., 10, 11 



sagittal plane, 3 

 Samassa, 5, 6, 8, 9, 16 

 Selenka, 16 



sense organ, 2, 4, 6, 12 

 spermatozoa. 9 

 stomach, in Coeloplaua, 17 

 stomodaeum, 2, 12, 19 

 Stylochus, 19 

 sub-costal canals, 4 

 sub-sagittal canals, 4 



— organs, 3 

 sub-transverse canals, 4 



— organs, 3 



tentacle sheath, 7 



tentacle stem, 7 

 tentacles, 2, 6, 12 

 tentacular base, 6 



— filaments, 8 



— plane, 3 

 Tentaculata, 19 

 transverse plane, 3 



— vessels, 4 

 Turbellaria, 19 



Vexillum, 21 

 Volvox, 1 



WlUey, 16, 18 



Printed by R. & R. Clark, Limited, Edinburgh. 



