CONTEMPOEAEIES AND SUCCESSORS OF EOZOON. 153 



Fig. 39. ArcJiceocyathus profundus — showing the base of attach- 

 ment and radiating chambers. {After Billings.) 







Fig. 40. Archceocy'athus Atlanticus — showing outer surface and 

 longitudinal and transverse sections. {After Billings.) 



