REPORT ON THE HEXACTINELLIDA. 9 



Genera : — Euplectella, Owen, Hahrodictyon, Wyville Thomson, Aphrocallistes, 



Gray, Farrea, Bowerbank, Aulodictyon, Kent, MacAndrewia, Gray, Dacty- 



localyx, Stuchbury, Fieldingia, Kent. 



II. Callicispongi^e, S. Kent. Sponge body supported by an interlacing or isolated 



spicular skeleton ; never by a reticulate and continuous one. Reproductive gemmules 



membranous, furnished with protective spicules. 



Genera : — Pheronema, Leidy, Hyalonema, Gray, Asconema, Kent, Sympagella, 

 0. Schmidt, LanugineUa, 0. Schmidt, Vazella, Gray. 

 In his Grundziige der Zoologie, Glaus maintained the union of the spicules into a 

 firm network to be an important character of all Hexactinellida (which constitute his 

 suborder of Hyalospongite), while Carter, 1873, like Saville Kent, only emphasised the 

 differences in the modes of union of the spicules as the main basis of his classification. 

 Carter ^ established the three following families : — 



I. VlTREOHEXACTINELLIDA. 



Spicules held together by silicified fibre. 



Dactyloccdyx, Myliusia, Euplectella aspergillum, Aphrocallistes, Atdodictyon, 

 Farrea, Sympagella. 



1. Patulina. Example — Dactylocalyx immiceus. 

 Gray. 



2. Tubulina. Example — Euplectella aspergillum, 

 Owen. 



3. Scopulifera. Example — Aphrocallistes hocagei, 

 Wrio;ht. 



Including the three groups <| 



II. Sarcohexactinellida. 



Spicides held together by amorphous sarcode. 



Asconema, Crateromorpha, Rossella, Hahrodictyon, Hyalonema, Pheronema, 

 Meyerina. 



1. Eosettifera. Example — Rossella, Carter, and Cratero- 

 morpha meyeri, Gray. 



2. Birotulifera. Example — Hyalonema sieholdi, Gray; 

 Holtenia, Wyv. Thomson; Meyerina, Gray, and 

 Labaria, Gray. 



Including the two groups 



III. Sarco-vitreohexactinellida. 



Spicules held together in one part by vitrified fibre, in the other by amorphous 



sarcode. 

 Euplectella cucumer, Owen. 



1 Ann. and Mag. Nat. Hist, ser. 4, vol. xii. y. 349 ; vol. xvi. p. 199. 

 (ZOOL. CHAIX. EXP. — PAET LIII. — 1886.) "S8 "^ 



