PLATE LVI. 



Figure 1. CidariSj sp. A part of a test, natural size (page 372). 



3. Ambulaeral plates, magnified. 



3. Coronal plates of a species of Cidaris, magnified (page 373). 



4. Portions of a Salmacis, magnified (page 374) . 



5. Temnopletjrus simplex, Duncan and Sladen (page 375). The test, natural size. 



6. Part of the test near the peristome, slightly magnified. 



7. Ambulaeral plate, magnified. 



