PLATE XXIII— Continued. 



Proetus Prouti 



Page 126. 

 Fie. 16. A nearly entire individual from which :i portion of the side of the cephalon and thorax has been 



broken away. 

 Fig-. 17. A profile of tin- same, showing the elevation of the body. 



Hamilton group. Smith's quarry, Davenport, Iowa. 

 Fig. 18. An imperfect individual, showing the axial nodes on the posterior thoracic segments. 

 Hamilton group. Cook's quarry, Davenport; Iowa. 

 The specimens represented in these two figures are the originals of Proetus Davenportenxis, 

 Barns. 



Proetus Nevad.k. 



Page 1'29. 

 Fig. 19. A nearly entire individual, showing the elongate body, narrow glabella and small eyes. 

 Devonian limestones. Comb's Peak, Eureka District, Nevada. 



Proetus Rowi. 



Page 119. 

 See Plate 21. 

 Fig. 20. A large entire individual. 



Hamilton group. Centerfield, Ontario county. 

 Fig. 21. A somewhat imperfect specimen, retaining the crust and showing the glabellar furrows. 



Hamilton group. Eighteen-mile Creek, Erie county. 

 Y\e. 22. A smaller, nearly entire individual. 



Hamilton group. Centerfield, Ontario county. 

 Fig. 23. A young individual, showing the very large eyes. 



Hamilton group. Centerfield, Ontario county. 

 Pig. 24. A still younger example. 



Hamilton group. < enterfield, Ontario county. 

 Fi' r . 25. A small individual in which two of the thoracic segments have been pushed forward beneath the 

 cephalon. 



Hamilton group. In the drift, Ann Arbor, MicMgan. 

 Fig. 26. Two entire individuals of average size. 



Hamilton group. Centerfield, Ontario county. 

 Fig. 27. The specimen figured on plate 21, tig. 25, drawn natural size. 



Tully limestone. Nit a- odd, .s, men county. 

 Fig. 28. A small individual, retaining a portion of the test and showing the essential features of the species. 



Tully limestone. Near Odd, Seneca county. 

 Fig. 29. An hypostoma. 



Hamilton group. Centerfield, Ontario county. 



Proetus macrooepiialus. 



Page 116. 

 See Plate 21. 

 Fig. 30. A nearly entire individual. 



Hamilton group. Canandaigua Lake. 

 Fig, 31. The pygidium of a very large example. 



Hamilton group. Canandaigua Lake. 



Pkoktus MlSSOURIENSls. 



Page 133. 

 Fig. 32. A portion of tin- cephalon. 



This specimen is the original of Pro, ins anriculatus, Hall (Fifteenth Kept. N. Y. Slate Cab. Nat. 

 Hist., p. 107, 1S62), from the Waveiiy group, Licking county, Ohio. 



