PLATE IV. 



HOMALONOTUS DeKAYI. 

 See Plates 2, 3 and 5. 

 Fig-. 1. Profile view of an unusually large enrolled individual, a cast of the lower surface. 

 Anterior aspect of the same, showing- the pygidial doublure. 

 Posterior aspect of the same. 



Hamilton group. Madison eowity. 

 Dorsal aspect of a normal cephalon. 



Lower aspect of the same, showing- the doublure, the branches of the facial sutures and the 

 median frontal plate. 



Hamilton group. Madison county. 

 Fig-, tj. An enlargement, to five diameters, of the under surface of the test, of a specimen from the soft 

 shales, showing the openings and projecting edges of the large vertical tubules. 

 Hamilton group. Canandaigua Lake. 

 Fig. 7. A similar enlargement of the under surface of a specimen from the limestone, showing the ele- 

 vated edge of the tubules and the openings of the minute tubulipores. 

 Hamilton group. Canandaigua Lake. 



