Plate 160. 

 1-3. Echinocardium dubium A. Ag. & CI. X 4. 



1. Abactinal view of holotype (St. 5047), partly restored and diagrammatic. 



2. Posterior view of same. 



3. Peristomial region. 



4. Hemiaster. 



4. Hypothetical apical system, to show passage from an ethmophract to an ethmolytic 



condition. 



5. Hemiaster globulus A. Ag. & CI. 



5. Peristomial region. X 2. 



