Plate 58. 



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



1. Side view. 



2. Abactinal view, showing the white star. 



3. Actiual view. 



4. Abactinal view of denuded test. 



5. Actinal view of same. 



6. Ambulacral view of same. 



7-8. Aspidodiadema meijerei A. Ag. and CI. 



7. Abactinal view of a specimen from Station 3839, in which the abactinal system is 



hypertrophied by several parasitic gasteropoda (Sty lifer ?). 



8. Abactinal view of the same specimen, with abactinal system denuded to show the 



modification of the genital and ocular plates. 



All figures natural size. 



