PLATE V. 



HoMALONOTUS DlCKAYI. 



See Plates 2, 3 and 4. 



Fig i. A verj young individual, showing the faint lateral furrows on the glabella. 

 Hamilton group. Pratt's Falls, Onondaga county. 



Pig. 2. Profile view of an un npressed, partially enrolled, entire individual, retaining the crust and the 



visual surface of the eyes. 

 Fig. :'.. Front view of the same, showing the elevation of the eyes. 



From the limestone of the Hamilton group. Canandaigua take. 

 Fig. 4. Profile view of an enrolled and compressed specimen from the shales. 

 Fig 5. Anterior aspect of the same. 

 Fig. 6. Posterior aspect of the same. 



Hamilton group. Western New York. 

 Fig. 7. A cephalon of medium size. 

 Fig. S. Profile view of the same. 



Hamilton group. Madison county. 

 Fig. 9. An imperfect cephalon. This specimen is the original of Eaton's Nnttainia sparsa and was 

 obtained by the author in March. 1832. at Stephen's Mill in the town of Coeymans, Albany 

 comity. The occipital ring was regarded by Eaton as the anterior border of the head, corres- 

 ponding to that of Trin net i us (Nnttainia) concentricus. (See Eaton's Geological Text-book, 

 page 34, 1832.) 

 Fig. 1(1. A small pygidium from the limestone, retaining normal convexity. 

 Fig. II. Profile view of the same. 



Hamilton group. Pratt's Falls. Onondaga county. 

 Fig. 12. Profile view of a pygidium, a cast, of the lower surface. 

 Fig. 13. Dorsal aspect, of the same, showing the usual character of the annulations. 



Hamilton group. Madison county. 

 Fig. 14. A c:ist .if the lower surface .4' a pygidium upon which the annulations are abnormally distinct for 

 so advanced a stage of growth. 

 Hamilton group. Madison county. 



