74 



SECTIONAL ADDRESSES. 



APPENDIX C. 

 Proposed Classification of Sponges and Suggested Genealogy. 



Choanoflagellata 



Proterospongia 

 MICROPHAGA 



Porifera nuda Porifera vera 

 (Hexactinellida) 



Orthogonida 



Clavulida 

 (with Hymeniacidori) 



Desmacidon 



Ceratosa 



(with 



Halisarca) 



Tetraxonida s.s. 

 (with Oscarella 

 and with Donatio) 



Calcarea 



ida 



Axinellida ? Renierida 



(with Spongillidae 

 and Chalinidae ; 

 without Halt- 

 clwndria) 



ENTEROZOA 



Orthogonida are defined ; — Sponges resembling Porifera vera in hydraulic system, 

 but having spicules formed of opal crystallising obscurely on the cubic 

 system. Macroscleres of monaxon facies. 



