Bd VI 4) 



THE ECHINOIDEA. 



I0 7 



Fie. 



Plate V. 



Arbacia crassispina Mrtsn. Actinal side. 



» » » Side view. 



» » » Abactinal side. Figs. 1 — 3 represent the same spe- 



cimen. 



» Dufresnii (Blv.). Abactinal side. 



» » » Side view. Same specimen as Fig. 4. 



» alternans (Troschel). Type specimen. Abactinal side. 



» » » » » Side view. 



» Dufresnii (Blv.). Actinal side. Same specimen as Figs. 10 — n. 



» » » Side view. Same specimen as Fig. 12. 



» » » » » » » » Figs. 8 and 11. 



» » » Abactinal side. » » » » 8 » 10. 



Fig. 9. 



africana (Troschel). Side view. 

 » » Actinal side. 



» » Abactinal » 



All the figures natural size. 



Plate VI. 



1. Loxechinus albus (Mol.). Abactinal side. 



Actinal 



Abactinal side. 

 Side view. 



» 7 — 8. Sterechinus Neumayeri (Meissn.). Abactinal side. 



» 9. Sterechinus Agassizii Mrtsn. Abactinal side. 



» 10. » » » Side view. 



» 11. » » » Abactinal Side. 



» 12. » » » Actinal side. 



Figs. 1 — 2 and 5, figs. 3 — 4 and 6, and figs. 10 — 12 represent the same specimen in 

 different views. 



All the figures natural size. 



Plate VII. 



Fig. 1. Sterechinus Neumayeri (Meissn.). Abactinal side. 

 » 2. » d » Actinal side. Same specimen as Fig. r. 



» 3. » Agassizii Mrtsn. Abactinal side. 



» 4. » Neumayeri (Meissn.). Abactinal side. 



All the figures natural size. 



