Fig. 



2. 



Fig. 



8. 



Fig. 



4. 



Fig. 

 Fig. 



5. 



6. 



Carboniferous Trilobites. 105 



PI.ATE III. 



Kig. 1. Pi'octiis Mhsonricimf<, Sbuuiard. 



A tigure of the head, showing the position of tlic pores, out- 

 side of the dorsal furrows of the glabella, — the so-called or- 

 gans of hearing. 

 The glabella, after Dr. Shumard's original figure (Geol. Mis- 

 souri, pi. B, fig. 13. 

 Proetus elUpticus, Meek and Worthen. 



Outline sketch from the original figure. 

 Griffithidesbufo, Meek and Worthen. 



The head enlarged twice, figure drawn from a specimen from 

 Craw^fordsville, Indiana, in Amer. Mus. Nat. Hist., N. Y, 

 The same, profile view^ 

 PhiUips'm Stevensoni, Meek. 



Outline sketch of the pygidium twice enlarged. Specimen 

 from the Chester Group, West Virginia, in Prof. J. J. 

 Stevenson's collection. 

 Fig. 7. PhilUpsia Sangamonensis, Meek and Worthen. 



A copy of the original figure. 

 Fig. 8. . The pygidium, copy of the original figure. 

 Fig. 9. GriffitMdes PortlockVi, Meek and Worthen. 



A figure of an entire specimen, twice enlarged, from War- 

 saw, Illinois. Amer. Mus. ]^at. Hist., New York. 

 Fig. 10. The pygidium of Griffithideshufo. 



An outline sketch of a specimen from Crawfordville, Ind. 

 Amer. Mus. Nat. Hist., New York. 

 Fig. 11. GriffiitMdes scitula, Meek and Worthen. 



Copied from the original figure. 

 Fig. 12. A side view of the same. 

 Fig. 13. The pygidium of the same. 

 Fig. 14. PhilUpsia major, Shumard. 



Outline sketch of the pygidium, of a specimen from Kansas 

 City, Missouri. Columbia College Museum. 

 Fig. 15. PhilUpsia Meramecensis, Shumard. 



The pygidium, copied from the original figure. 

 Fig. 16. The pygidium of Proetus Missouriensis. 

 Copied from the original figure. 



