PLATE XXI— Continued. 

 Proetus MACROCEPHALUS. 



Page 116 

 See Plate 23. 

 Fig. 10 An obliquely crushed individual, retaining the right eye and fixed cheek. 



Hamilton group. Canandaigua Lake. 

 Fig. 11. A large imperfect individual. 



Hamilton group. Jaycox's Bun, near Q-eneseo, Livingston county. 

 Fig. 12 An imperfect specimen, wanting- the free cheeks as is usual. 



Hamilton group. Cayuga Lake. 

 Fig. 13. A portion of th phalon, showing, by compression, the glabellar furrows. 



Hamilton group. York, Livingston county. 

 Fig. 14. An entire cephalon, also showing some of the glabellar furrows. 



Hamilton group. Canandaigua Lake. 

 Fig. 15 The pygidium of a small individual, enlarged to two diameters. 



Hamilton group. Near Geneseo, Livingston county. 

 Fig. 16. A pygidium from the limestone, similarly enlarged. 



Hamilton group. Eighteen-mile Creek, Erie county. 

 Fig. 17. A pygidium, showing the internal surface and the doublure. 



Hamilton group. Canandaigua Lake. 

 Fig. 18. A pygidium enlarged to two diameters, showing the axial nodes which give the animations the 

 appearance of being medially angulated. 



Hamilton group. Locality ? 

 Fig. 19. A large pygidium. 



Hamilton group. North Bristol. Ontario county. 

 Fig. 20. Profile view of the pygidium represented in fig-. 15. 

 Fig. 21. Profile view of the pygidium represented in fig. 16. 



Proetus occidens. 



Page 130. 

 Fig. 22. A small pygidium retaining the crust, but nOt in such condition as to show the annulations with 

 distinctness. 



Hamilton group? New Buffalo, Iowa. 

 Fig. 23. A large imperfect specimen. 



Hamilton group? New Buffalo, Iowa: 



Pkoetus Conradi. 



Page 89. 



See Plates 20 and 22. 



Fig. 27. Anterior view of an enrolled, somewhat imperfect individual, showing the proportions of the 



glabella and the wide, sloping border. 

 Fig. 28. Posterior view of the same. The axis of the body is made to appear too broad and stout. 

 Schoharie grit. Schoharie, Schoharie county. 



CyPIIASPIS LjEVIS. 

 Page 150. 

 Fig. 29. The cephalon enlarged to twelve diameters. 



( Ihemung group. Chi muni/ county. 



