Plate 70. 

 Arseosoma thetidis A. Ag. and CI. 



1. Abactinal system. X 1.7. 



2. Actinostome and base of corona. X 1.1. 



3. Actinal ambulacral and interambulacral plates, ten millimeters from ambitus. X 1.3. 



4. Abactinal ambulacral and interambulacral plates, ten millimeters from ambitus. X 1.1. 



