1886.] POSITION AND CLASSTFICATION OF SPONOES. 589 



1. Subfamilia SpongeUna, Lendenfeld. 



Without flesh-spicules. The skeleton consists of distinct horny 

 fibre containing a varying amount of foreign matter. 



Spongelia, Nardo ; Dysidea, Johnston ; and Reteplax, Lenden- 

 feld, MS. 



2. Subfamilia Psammmce, nov. 



The skeleton consists of foreign bodies cemented by spougin, 

 which, however, is not distinctly visible ; without flesh-spicules. 



Psammapemma, Marshall ; Psammella, Lendenfeld, MS. ; and 

 Holopsamma, Carter. 



3. Subfamilia Spongelissince, Lendenfeld. 

 The skeleton is composed of distinct horny fibres containing 

 foreign bodies. "With flesh-spicules. 

 Dysideissa, Lendenfeld, MS. 



4. Subfamilia Psammopessince, nov. 



The skeleton consists of cemented foreign bodies without distinct 

 horny fibres. With flesh-spicules. 



Psammopessa, Lendenfeld, MS. ; Phoriospongia, Marshall ; and 

 Haastia, LendenfelJ, MS. 



5. Familia Aplysillid^, Lendenfeld. 

 The skeleton consists of spongin-tubes ramified in a dendritic 

 fashion and filled with pith. 



I. Subfamilia AplysillitKs, Lendenfeld. 



Cells are found in the pith of the fibres only. 

 Darwinella, Fritz Midler ; Aplysilla, F. E. Schulze ; Verongia, 

 Bowerbank ; and Bendrilla, Lendenfeld. 



2. Subfamilia lanthellince, nov. 

 Cells are found in the spongin-sheath of the fibre. 

 lanthella, Gray. 



6. Famiha Halisarcid^, Vosmaer. 



Without skeleton. 



Halisarca, Schmidt, and Bajalus, Lendenfeld. 



V. Key to the Recent Families of Sponges. 



f Skeleton calcareous .. 1. 



\ No calcareous skeleton (2.) 



Entoderm consists exclusively of collar-cells ... 3. 



Entoderm consists of collar- and pavemeut- 



cells (4.) 



r Mesoderm thin, gastral cavity h-regular 1. Ascmidce. 



\ Mesoderm thin, radial cylindrical chambers ... 2. HmnodermidcB. 



\ Mesoderm thick, irregular chambers 3. Leucopdidce. 



