Plate XX. 



Fie. 



I. 



2. 



3- 

 4- 



5- 

 6. 



7- 

 8. 



9- 

 I o. 

 II. 



12. 



13- 

 H- 



15- 

 1 6. 



1 8. 

 19. 

 20. 

 21. 

 22. 



23- 



24. 



25- 



26. 

 27. 

 28. 

 29. 

 30- 



Tridentate pedicellaria of Echiniis Alexavdyi. Obj. o. Oc. I. 



Spicules of Echiiius Alexandri. Obj. V. Oc. I. 



Valve of a triphyllou.s pedicellaria of Strongylocentrotus drøbachievsis. Obj. II. Oc. III. 



— — tridentate — - — — i.graiiitlatus. Obj.o. Oc. I. 



— — ophicephalous — - — — Obj. II. Oc. III. 



— — tridentate — - — — Obj. o. Oc. I. 



— — triphyllous — - Sterechiints Neumayeri. Obj. II. Oc. III. 

 Spicnles of Echinus elegans. Obj. V. Oc. I. 



Tridentate pedicellaria, small form, of Echimis elegans. Obj. II. Oc. o. 



Valve of a tridentate pedicellaria of Strongylocentrotus pidclien'iiiins. Obj. II. O c. o. 



Tridentate pedicellaria of Sterechiims Neitiuayeri. Obj. o. Oc. I. 



Spicnles of Strongylocentrotits drøbachiciisis. Obj. V. Oc. I. 



Sphæridia of — — Obj. II. Oc. III. 



Valve of a globiferous pedicellaria of Strongylocentrotus pitrptiratus^ from the inside. Obj. II. Oc.o. 



Globiferous pedicellaria of Psammechinns variegatus. Obj. II. Oc. o. The skin full of spicules. 



Valve of a globiferous pedicellaria of Strongylocentrotus drøbac/u'ens/s, from the inside. 



Obj. II. Oc. I. 

 Spicules of Echinus a/fims. Obj. V. Oc. I. 



Sphæridia of Strongylocentrotus drøbachiensis. Obj. II. Oc. III. 

 Tridentate pedicellaria, large form, of Eclu'n/ts elegans. Obj. o. Oc. o. 

 Valve of a tridentate pedicellaria of Strongylocentrotus drøbachiensis. Obj.o. Oc. I. 



— — triph\llous — - Echinus affinis. Obj. II. Oc. III. 



— — — — - — elegans. Obj. II. Oc. III. 

 Stalk of a globiferous pedicellaria of Echinus elegans. Obj. II. Oc. I. 

 Spine from the buccal piates of Echinus esculentus. Obj. o. Oc. o. 



Globiferous pedicellaria, the neck protruded, of Strongylocentrotus drøbachiensis. The spicules 



are drawn only on the upper side of the head. Obj. o. Oc. I. 

 Valve of a globiferous pedicellaria of Strongylocentrotus drøbachiensis, from the side. Obj. II. Oc. I. 



— — ophicephalous — large form, of Echinus Alexandri. Obj. II. Oc.o. 



_ — globiferous — of Strongylocentrotus purpuratus, from the side. Obj. II. Oc. o. 



Globiferous pedicellaria, the neck retracted, of Strongyloc. drøbachiensis. Obj. o. Oc. III. 

 Spine of Echinus esculentus, the basal part. Obj. o. Oc. o. 



