Natural Science, vol, vii. 



[Plate IX. 



ECHINOIDEA 



Fig. 1. Acrope rosiraia, Thoms. Fig. 2. Cystechinus uyvillei, A. Ag. ; 

 spines removed. Fig. 3, Pourtalesia ceratopyga, A. Ag. ; the abactinal surface, 

 covered with spines. All nat. size. Fig. 4. Hemiaster cavernosus (Phil.) ; one 

 of the marsupial recesses, with eggs inside, x 5. 



