PLATE LI. 



Figure 1. Echinodiscus Desori, Duncan and Sladen (page 338). Actinal view, natural size. 



2. An outline of a test of the same species. 



3. A variety of the species, abactinal view. 



4. Abactinal view of another variety (page 328). 



5. Abactinal view of the same variety. 



6. A magnified view of the lunule from below. 



7. EcHiNODiscus PLACENTA, Duncan and Sladen (page 329). Portion of an inter- 



radium and ambulacra, slightly magnified. 



8. EcHiNODiscTJS Desori. Broken test, showing the crushed jaws from above, and 



some of the supporting structures between the upper and lower parts of the test. 



9. Part of the same, magnified. 



10. EcHiNODiscus ELONGATUS, Duncan and Sladen (page 331). The test in outline, 



natural size. 



11. ECHINODISCUS ELLiPTicus, Duucau and Sladen (page 330). The test, natural size. 



1 2. ECHINODISCUS Desori, var. Side view of a portion of a test, showing the plates and 



pillars in section. 



