506 M. K. A. Zittel on Fossil Hexactinellida. 



Staueonema, Sollas. 



Ann. & Mag. Xat. Hist. 1877, vol. xix. 



Sponge-bodj lamellar, somewhat bent round at the lateral 

 margins, convex on one side, concave on the other, attached bj 

 the narrowed base. Wall thick, with numerous straight perfo- 

 rating canals standing in quincunx. The skeleton consists 

 of a verj regular latticework of rather large sexradiates, the 

 arms and solid crossing-nodes of which are so considerably 

 thickened that the meshes acquire a small lumen and a rounded 

 form. Both surfaces are coated with a thin siliceous mem- 

 brane, which is perforated bj innumerable, unequal-sized, 

 rounded, or irregularlj-formed pores and orifices. This porous 

 covering layer also veils the ostia of the canals. 



Stauronema Carteri and lohattij Sollas. 



Family 5. Ventriculitidae. 



Pachtteichisma, Zitt. 



Top-shaped or basin-shaped, with very thick walls consist- 

 ing of perpendicular masandric folds. On the outer wall the 

 folds are separated by deep, and on the inner wall by shallow, 

 longitudinal furrows. In the interior of the folds there are cacal 

 radial canals, the round ostia of which stand in longitudinal 

 rows upon the stomach-wall. By friction of the surface the 

 canals are also frequently visible externally. Skeleton con- 

 sisting of very regularly arranged large sexradiates with octa- 

 hedral crossing-nodes. Covering layer and root wanting. 



PacJiyteichisma Carteri ^ Zitt. ( = Fungit. Knorr u. Walch, 



Petref. tab. F. 3, no. 48, fig. o). 

 Spongites lopas^ Quenst. Jura, 83. 5. 



Teochobolus, Zitt. 



Top-shaped or cylindrical, thick-walled, ^vith a rather 

 narrow central cavity. Surface with glebiform elevations, 

 separated from each other by deep furrows. The ostia of the 

 generally tortuous radial canals are situated on the wall of the 

 body-cavity. Skeleton like that of the preceding genus, but 

 the meshes considerably smaller. Covering layer and root 

 wanting. 



TrocJioholus crassicosta, Zitt., n. sp. (Upper Jura, Streit- 



berg.)_ 

 ScypMa texata, Goldf. xxxii. 4. 



i 



