16 



INTEODUCTION. 



Thecosiphonia, Z'ltt. 

 Calymmatina, Zitt. 

 Turonia, Mich. 

 Kalpiaella, Hinde. 

 Thamnospongia, Hinde. 

 Pliolidoclaclia, Hinde. 

 Ragadiriia, Zitt. 

 Plinthosella, Zitt. 

 Phymaplectia, Hinde. 

 Rhopalospongia, Hinde. 



Order Hexactinellid^. 



Suborder Di ex yon in a. 



Family AsTYLOspoNGiDiK. 

 Astylospongia, Earner. 

 Palseomanoiij Rcemer. 



Family Euretid^. 

 Tremadictyon, Zitt. 

 Craticularia, Zitt. 

 Sphenaulax, Zitt. 

 Sporadopyle, Zitt. 

 Strepliinia, Hinde. 

 Verrucoccelia, Etallon. 

 Stauronemaj SoUas. 

 Sestrodictyon, Hinde. 

 Brachiospongia, Marsh. 



Family Coscinoporid^. 

 Leptopliragma, Zitt. 

 Pleurostoma, Romi. 

 Guettardia, Mich. 

 Coscinopora, Gold/. 



Family Mellitionid^. 

 Aphrocallistes, Gray. 



Family Ventricdlitid^. 

 Pachyteichisma, Zitt. 

 Trocliobolus, Zitt. 

 Plilyctserxium, Zitt. 

 Ventriculites^ Mantell. 

 Schizorhabdus, Zitt. 

 Rhizopoterion, Zitt. 

 Sporadoscinia, Pom. 



Sestrocladia, Hinde. 

 Polyblastidium, Zitt. 

 Ceplialites, Toulmin Smith. 



Family Staurodermid.i:. 



Cypellia, Pom. 

 Staurodermaj Zitt. 

 Purisiphonia, Bowb. 

 Porocypellia, Pom. 

 Casearia, Quenst. 

 Porospongia, D'Orbigny. 

 Oplirystoma, Zitt. 

 Cinclidermaj Hinde. 

 Protospongia^ Salter. 

 Dictyophyton, Hall. 

 Eubrochus, Sottas. 



Family Meandrospongid,b. 



Plocoscyphia, Reuss. 

 Tremabolites, Zitt. 

 Etheridgia, Tate. 

 Toulminia, Zitt. 

 Camerospongia, D'Orbigny. 

 Cystispongia, Rcemer. 



Family Callodictyonid^. 



Callodictyon, Zitt. 

 Poroclionia, Hinde. 

 Becksia, Schliiter. 

 Diplodictyon, Zitt. 

 Sclerokalia, Hinde. 



Family CffiLOPxycHiD^. 

 Cceloptyehium, Gold/. 



Suborder Lyssakina, Zitt. 



Family Monakid^, Marshall. 

 Astrseospongiaj Rcemer. 

 Stauractinella, Zitt. 



Family PoLLAKiDiEj Marshall. 

 Hyalostelia, Zitt. 

 Holasterella, Cart. 



iNCERTiE SEDIS. 



Amphispongiaj Salter. 



