CONTENTS. VII 



Keratosa — Continued. 



Family Spongidae — Continued. Page. 



Subfamily Aplysininae 487 



Psammaplysilla Keller 487 



kelleri, new species 488 



Subfamily Stelosponginae 491 



Hircinia Nardo 491 



mutans, new species 491 



variabilis F. E. Schulze 494 



Bibliography 497 



Explanation of Plates 507 



Index 523 



