PLATE III''. 



Farasalenia gratiosa, /. 1, 2. 



1. Seen in profile. 



2. Seen from the abactinal pole. 



Colobocentrotus atratus, /. S. 



3. Seen from the aliuutinal pole. 



Colobocentrotus Mertensii, /. jj, 5. 



4. Seen from the abactinal pole. 



5. Seen Irom the actinal pule. 



Heteroceutrotus trigonarius, /. G. 



6. Seen from the abactinal pole, f nat. size. 



(^AU Figs., except 6, natural she.) 



