M. K. A. Zittel on Fossil Lithistidce. 339 



inner (=upper) surface usually larger. Canal-sjstem, skele- 

 ton, and surface-lajer as in Verruculina. 



This is perhaps only a subgenus, its sole difference from 

 Verruculina being that the elevated oscula are not confined to 

 the inner surface. The outer oscula are generally smaller 

 than the inner, sometimes reduced to fine, rounded, elevated 

 pores. 



Pomel has referred the species to three genera ; but, curi- 

 ously, for the principal genus, Stelgis, a Hexactinellid ( Veiitri- 

 culites radiatusj Mant.) is cited as the typical species. 



All the species are from the Upper Cretaceous. 



1. Spongia osculifera^ Phill. Geol. Yorkshire, i. 3. Upper 

 Chalk 



2. Manon circumporosum^ Quenst. Petr. exxxii, 55, Se- 

 nonian. 



*3. Manon miliaris^ Reuss, Bohm. Kr. xix. 10-13. Ceno- 

 manian, 



4. Manon tenue, F. A. Rom, Kr, i. 7. Turonian, Ceno- 

 manian. 



Chenendopora tenuis, Qtieast. Petr. cxxxi. 8, exxxii. 44-48. 



5. Chenendopora crassa, Rom. Spong. xvi. 1. Cuvieri- 

 Planer. 



6. Spongia eonvoluta, Quenst. Petr. exxxii. 49, 50. Upper 

 Chalk. 



7. Verrucospongia macrommuta^ Rom. Spong. xvi, 4. 

 Senonian. 



8. Verrucospongia damcecomisj Rom. Spong. xvi. 5. Ce- 

 nomauian. 



Stichophyma, Pomel. 



Mnyion p. p. Rom., Reus.s. 

 Verrucospongia y. p., D'Orb., Rom. 

 Polyjerea p.p., Rom, 

 Stichophyma, Pom. 



Sponge simple, rarely branched, cylindrical, clavate, top- 

 shaped or nodular. At the vertex some usually margined and 

 somewhat prominent orifices of vertical canals which penetrate 

 the whole height of the sponge-body. On the sides also there 

 are usually wart-like oscula, sometimes replaced by simple 

 round apertures, communicating with horizontal canals. Be- 

 sides these larger canals, fine radial canals run from the central 

 axis towards the periphery. Base generally narrowed, but 

 not stalked. 



Skeleton composed of small, short, crooked, irregular cor- 

 puscles with many branches, covered on all sides with short 

 root-like processes. At the surface these are sometimes very 



23* 



