PLATE XI i.. 



DALMANITES (OdONTOOEPHALUS) . Kc;ki;i \. 

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 Fie. 1. The cephalon. A. cast of the internal surface from which the eyes have been broken; showing 



the eleven denticiilations on the frontal margin and the long, slender genal s] 

 Fig. 2. Profile of the sane-. 



Opper Helderberg limestone. Williamsville, Eru county. 

 Fig. 3. A nearly . -n t "n-.- individual, enlarged to two diameters, showing the distinguishing features of the 

 species. The pygidium has ' n drawn too narrow and constricted near the posterior extrem- 

 ity, and the caudal spines too I 

 Fig. 4. Profile of the same. 



Corniferous limestone. Chittenango, Madison county. 

 Fig. 5. Dorsal view of the frontal cephalic border, enlarged to two diameters, showing the shape and 

 number of the denticulations. 



Upper Helderberg limestone Williamsville, Brit county. 

 Fig. 6. Lower surface of the frontal doublure, enlarged to two diameters, showing the incisor-like form 

 of the denticulations and the openings of the vertical tubuli pores. 

 Upper Helderberg limestone. Williamsmlle, Erie county. 

 Fig. 7. A pygidium, showing unusually long terminal spines. 



Upper Helderberg limestone. Williamsville, Erie county. 

 Fig. 8. A smaller pygidium. 

 Fig. 9. Profile view of the same. 



Upper Helderberg limestone. Williamsville, Eru county. 

 Fig. 10. A pygidium of average size, showing normal i roportions. 



Upper Helderberg limestone. Schultz's Farm, near Clarence, Eru county. 

 Fig. 11. The axis of the pygidium. drawn from an internal cast, to show the median depression and obso- 

 lescem ; of the an n illations near ttie extremity. Enlarged to two diameters. 



Upper Helderberg limestone. Schultz's Farm, near Clarence, Erie county. 



I >AI.MANITKS (( )im ixit (CEPHALUS ''.) CORONATUS. 

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 Fig. 12. The pygidium and a portion of the thorax. The specimen shows the characteristic broadlj emar- 

 ginate, aspinose posterior extremity, and a somewhat shorter pygidium than in the associated 

 species. 



Corniferous limestone. Near Aubm , Cayuga county. 

 Fig. 13. The pygidium of the same specimen, introduced for comparison with the adjoining pygidia. 

 Fig. 14. An imperfect pygidium, referred with doubt to this species. 



Corniferous limestone. Schoharie, Schoharii county. 



Dalmanites (Odontooephalus) selenurus. 



Page 49. 

 See Plate 12. 

 Fig. 15. A pygidium preserving normal proportions and showing the divergent, slender terminal spines. 

 One side of the figure is somewhat restored. 



Corniferous limestone. Schoharie, Schoharii county. 

 Fig. 16. A small pygidium having more nearly parallel spines ; drawn from a east of the internal surface. 

 Fig. 17. The same, viewed in profile, showing- the ele\ atii n of the terminal spines. 



Corniferous limestone. C(tn<iiiilitir/ini. (hiti'i-'m county. 

 Fig. 18. A somewhat imperfect pygidium with the terminal spines inclined slightly inward. 

 Corniferous limestone. Phelps, Ontario county. 



