Plate 55. 



1-2. Pourtalesia Tanneri A. Ag. ; Station 3431. 



1. Seen from the actinal side. 



2. The same, seen in profile, facing the left posterior ambulacrum. 



3-5. Plexechinus cinctus A. Ag. ; Station 3424 



3. Seen from the actinal side. 



4. The same, seen from the abactinal side. 



5. The same, seen in profile, facing the left posterior ambulacrum. 



6-8. Aerope fulva A. Ag. ; Station 3361. 



6. Seen from the actinal side. 



7. The same, seen from the abactinal side. 



8. The same, seen in profile, facing the left posterior ambulacrum. 



9-10. Homolampas hastata A. Ag. 



9. Seen from the actinal side. 



10. The same, seen from the abactinal side. 



All figures natural size. 



