Clam. — The Cidaridae- 



PLATE 7. 



1-4. Tretocidaris perplexa, sp. nov. Nat. size. 



1. Abactinal view of partly cleaned specimen. 



2. Actinal view of same. 



3. Interambulacral view of same. 



4. Ainbulacral view of same. 



6-8. Dorocidaris rugosa, sp. nov. Nat. size. 

 6. Abactinal view of partly cleaned test. 



6. Actinal view of same. 



7. Interambulacral view of same. 



8. Ambulacral view of same. 



