PERMIAN FOSSILS 



433 



the Trilobites, which henceforth we shall meet with no more, and 

 the Eurypterids have entirely disappeared. Little is known con- 

 cerning the other Arthropods of this period. 



Bryozoa are prominent in all marine formations, sometimes 

 forming reefs. 



Plate VII. American Permian Fossils 



i. Aviculopecten occidentalis. 2. Myalina permiana, 2/3. 3. Nautilus Winslowi. 

 4. Medlicottia Copei, 2/3. 5. Callipteris conferta, 1/2. 6. Sphenopteris coriacea, 

 3/4. (Figs. 1-4 after C. A. White. Figs. 5, 6 after Fontaine and I. C. White.) 

 2 F 



