PLATE IV. 
Homalonotus Dekayi. 
See Plates 2, 3 and 5. 
Fig. 
1. 
Fig. 
2. 
Fig. 
3. 
Fig. 
4. 
Fig. 
5. 
Fig. 
6 . 
Fig. 
7. 
Profile view of an unusually large enrolled individual, a cast of the lower sui-face. 
Anterior aspect of the same, showing the pygidial doublure. 
Posterior aspect of the same. 
Hamilton group. Madison county. 
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. 
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. 
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. 
