PLATE XXill. 



Stomechinus Hyatti Clark (page 56). 



Fig. la. Lateral surface view of the test, slightly distorted. 

 1/*. Portion of the ambulacral area, enlarged. 

 Ic. Portion of the interarabulacral area, enlarged. 

 Id. Tubercle from above, highly magnified. 

 le. The same from the side. 



HOLECTYPUS PLANATUS Eoeuier (page .58). 



Fig. 2a. Upper surface of the test. 

 26. Lower surface of the same. 

 2c. Lateral surface of the same. 

 2d. Two interambulacral plates, enlarged. 

 2€. Portion of the ambulacral area, highly magnified. 

 2/. Apical disk, enlarged. 

 150 



