Plate lio. 

 1-3. Echinus atlanticus Mrtsn. 



1. Abactinal view of unusually fine specimen; Ascension Island. 



2. Side view of same. 



3. Actinal view of same. 



4, 5. Heliocidaris stenopora, nom. nov, 



4. Abactinal view of A. Agassiz's type of Toxocidaris mexicanus, partly denuded. 



5. Side view of same. 



All figures, natural size. 



I 



