Hambach — Revision of the Blastoideae. 37 



In a lateral view the base is never visible. For com- 

 parison seethe accompanying figure 12. 



2. Pentkemites ANGULAKis, Lyon, 1860. Chester limestone. 



3. Pentremites basilaris, Hambach, 1880. Chester lime- 



stone. 



4. Pentremites Broadheadi, Hambach, 1880. Chester 



limestone. 



5. Pentremites burlingtonensis. Meek & Worthen, 1869. 



Burlington limestone. 



6. Pentremites GAL YCiNUS, Lyon, 1860. Chester limestone. 



7. Pentremites cervinus. Hall, 1858. Chester limestone. 



8. Pentremites chesterensis, Hambach, 1880. Chester 



limestone. 



9. Pentremites clavatus, Hambach, 1880. Chester lime- 



stone. 



10. Pentremites conoideus, Hall, 1856. Warsaw limestone. 



This species is synonymous with Pentremites Icon- 

 inckana, Hall, which is only the young stage of 

 P. conoideus. 



11. Pentremites elegans, Lyon, 1860. Chester limestone. 



This species is synonymous with the one designated 

 by Dr. Troost as tennesseae, nom. nud. The descrip- 

 tion of Troost was never published. The specimens 

 so designated by Troost, now in the collection of the 

 Smithsonian Institution, No. 33,072, are the same as 

 those described by Lyon as Pentremites elegans. 



12. Pentremites elongatus, Shumard, 1855. Burlington 



limestone. 



13. Pentremites florealis, v. Schlotheim, 1820. Chester 



limestone. 

 Pentremites symmetricuSj Hall. Chester limestone. 

 Pentremites altus, Rowley. 



