PLATE XIII. 



Figure 1. Plesiolampas rostrata, Duncan and Sladen (page 61). The abactinal surface. 



2. The side view. 



3. The periproct, natural size. 



4. Plesiolampas placenta, Duncan and Sladen (page 54) . Actinal surface. 



5. Another specimen, abactinal surface. 



6. Part of an ambulacrum, magnified. 



7. The peristome, slightly magnified. 



8. The peristomial margin, with an ambulacrum and faint bourrelets, magnified. 



9. The longitudinal outline. 



10. Plesiolampas polygonahs, Duncan and Sladen (page 61). The abactinal surface. 



11. The longitudinal outline. 



