Plate 55. 



1-6. Centrostephanus asteriscus A. Ag. and CI. 



1. Actinal view of denuded test, x 4. 



2. Abactinal view of same. X 4. 



3. Side view of same, showing left anterior ambulacrum, x 4, 



4. Actinal portion of odd anterior ambulacrum, x 10. 

 6. Basal half of primary spine. X 5. 



6. Base of same, x 10. 



7-10. Leptodiadema purpureum A. Ag. and CI. 



7. Actinal view of denuded test, x 5. 



8. Abactinal view of same. X 5. 



9. Side view of same, showing right anterior ambulacrum. X 6. 

 10. Basal part of primary spine. X 5. 



