PLATE XV. 



Clypeaster subdepressus AGABS. 



Fig. 1. Seen from above, natural size ; half the test denuded. 



Fjg 2. I yeen feoni the actinai side. 



Fi". 3. Part of one of the median ambulacral zones of the actinai side, somewhat magnified. 



Fig. 4. Part of one of tbe median interambulacral zones of tbe abactinal side, magnified. 



