58 



COELENTERATA SPONGIAE 



CLASS I 



nnwls short, ending blind. 



Framework compact, with fine meshes; dermal 

 layer replaced by thicken- 

 ing of outermost skeletal 

 layer. Spicular nodes solid, 

 more rarely perforate. 

 Cretaceous. 



Leptophragma, Zitt. 

 Beaker-shaped, with root- 

 like attachment. Walls 

 thin, covered on both 

 sides with small canal- 

 openings arranged in 

 alternating rows. Mesh- 

 work very closely woven, 

 spicular nodes solid. 

 Middle and Upper Cre- 

 taceous. 



Pleurostoma, Roem., 

 Guettardia, Mich. Cre- 

 taceous. 



Coscinopora, Goldf. 



(Fig. 75). Beaker -like, with branching roots. Ostia small, round, and in 



alternating rows. Skeletal elements in part with perforated intersection nodes. 



Root consisting of long silicious fibres. Dermal layer formed by thickening 



and fusion of outermost hexactins. Cretaceous. 



Coscinopora infundibttliformis, Goldf. Upper 

 Westphalia. , Complete individual, 1/2 natural 

 natural size ; c, Same, 3/i ; cl, Skeleton of cup, l^/j ; 



Cretaceous ; Coesfeld, 

 size ; b, Outer surface, 

 e, Skeleton of root, 12/j. 



Family 3. Staurodermidae. Zittel. 



Top-shaped, funnel-shaped, or cylindrical, moi'e rarely branching or in clumps. 

 Ostia and postica irregularly distributed, or in alternating rows. Skeletal framework 

 more or less regular; intersection n 7 



nodes thick or octahedrally excavated. 

 The outer, or both surfaces of the 

 wall provided with large, stellate 

 spicules (stauractins), which differ 

 from those of the rest of the skeleton, 

 and are either but loosely cemented 

 together, or are embedded in a con- 

 tinuous silicious skin. Jurassic and 

 Cretaceous. 



FIG. 70. 



Cypellia rugosa, Goldf. sp. Upper Jurassic; Stroll berg, 

 Franconia. a, Sponge, Va natural size; ft, c, Dermal layer, i-'/i- 



Zitt. (Fig. 76). Top- 

 shaped, bowl-shaped, or branching, 

 without root. Canals irregu- 

 larly distributed, crooked, and 

 branched. Lattice skeleton with 



irregular meshes, intersection 

 nodes perforated. Dermal layer composed of large, four-rayed stauractins 

 embedded in a thin, continuous, or perforated skin. Very common in Upper 

 Jurassic Spongitenkalk. 



