MERRILL : FOSSIL SPONGE SPICULES. 



25 



EXPLANATION OF THE PLATE. 



Fig. 1. 



Fig. 2. 



Figs. 3, 



Fig. 5. 



Fig. 6. 



Fig. 7. 

 Fig. 8. 

 Fig. 9. 

 Fig. 11. 



Fig. 12. 



Fig. 13. 



Fig. H. 

 Fig. 15. 



Fig. 16. 

 Fig. 17. 



Fig. 18. 



Fig. 19. 



Fig. 20. 



Fig. 21. 

 Fig. 22. 



Fig. 23. 



i 



Axinella ? sp. Replaced by chalcedonic silica. X 80 

 Axinella? sp. Replaced by chalcedonic silica- X 20 

 Monactinellid 



Monactinellid 



diameters. 



Monactinellid 

 diameters. 



4, 10, and 36. Monactinellid. Reniera ? sp. Bodies replaced by amor- 

 phous silica, canal by chalcedonic silica. X 80 diameters. 



Monactinellid, acuate spicule. Replaced by chalcedonic silica. X 80 

 diameters. 



Monactinellid. Spicules covered with minute projections, canal enlarged. 

 X 80 diameters. 



Monactinellid, dark outer covering, probably iron ore. X 80 diameters. 



Monactinellid. Replaced by amorphous silica. X 80 diameters. 



Esperia ? sp. In amorphous silica. X 80 diameters. 

 Geodia ? Austini, n. sp. In colloidal silica. X 275 diam- 



Monactinellid. 

 Tetractinellid. 



eters. 

 Tetractinellid. 



eters. 

 Tetractinellid. 



diameters. 

 Tetractinellid. 

 Tetractinellid. 



ameters. 

 Tetractinellid. 

 Tetractinellid. 

 Tetractinellid. 



eters. 

 Tetractinellid. 

 Tetractinellid. 



diameters. 

 Tetractinellid. Geodia? Hilli,n.sp. In colloidal silica ? X 275diameters. 

 Tetractinellid. Geodia tripunctata f n. sp. Fragments resulting from solu- 

 tion. X 275 diameters. 

 Lithistid ? Flesh spicule. X 275 diameters. 

 25. Tetractinellids. Hymeraphia? sp Globostellates in colloidal silica ? 



X 275 diameters 



Geodia? cretacea, n. sp. In colloidal silica ? X 275 diam- 



Geodia ? spini-curvata, n. sp. In colloidal silica ? X 275 



Geodia ? irregularis. In colloidal silica ? X 275 diameters. 

 Geodia ? tripunctata, n. sp. In colloidal silica. X 275 di- 



Hymeraphia 1 sp. X 275 diameters. 



Chondrilla ? sp. In colloidal silica 1 X 275 diameters. 



Geodia? Texana, n. sp. In colloidal silica. X 275 diam- 



tlymeraphia 7 sp. In colloidal silica ? X 275 diameters. 

 Geodia ? spini-pansata, n. sp. In colloidal silica ? X 275 



