18 ILLUSTRATIONS 



FIGURE PAGE 



1. Sketch map showing the biologic provinces of the Upper Devonian sea 



in the New York area. (After Clarke.) 28 



2. Diagram showing probable relations of the Upper Devonian faunas 



and sediments in Western Maryland and adjacent areas 29 



3. Diagram showing the manner in which spicules unite to form canals 



(modified from Rauff) 196 



4. Sketch showing the interlocking spicules of Hindia fibrosa. (After 



Rauff.) 196 



5. Diagram showing the spicules of Hindia fibrosa uniting to form a 



hexagonal canal. (After Rauff.) 197 



6. Analysis of Tetrecystis chrysalis Schuchert 232 



7. Analysis of Jsekelocystis hartleyi Schuchert 234 



8. Analysis of Jaekelocystis avellana Schuchert 235 



9. Analysis of Pseudocrinites gordoni Schuchert 237 



10. Analysis of Pseudocrinites abnormalis Schuchert 239 



11. Analysis of Pseudocrinites elongata Schuchert 242 



12. Analysis of Pseudocrinites perdewi Schuchert 243 



13. Analysis of Trimerocystis peculiaris Schuchert 244 



14. Diagrams showing the manner and number of ambulacral branches in 



a young, adult and old specimen of Sphserocystites multifasciatus 

 Hall 246 



15. Analysis of Sphserocystites multifasciatus Hall 246 



16. Diagrams showing the number of ambulacral branches in two speci- 



mens of Sphasrocystites globularis Schuchert 247 



17. Analysis of Sphserocystites globularis Schuchert 247 



