PLATE 4. 
Fig. 1. 18. 1. RETEPORA INCEPTA. (Pag. 15.) 
1 a. Specimen of the natural size. 1 6. An enlarged portion of the same. 
Fig. 2. 19. 2. ReETEPORA GRACILIs. (Pag. 15.) 
2a. Natural size of the fragment. 2. Enlarged portion, showing the form of the fenestrules. 
Fig. 3. 20. 1. Gorconta? ASPERA. (Pag. 16.) 
Fig. 
3 a. Natural size of specimen. 
3b. Portion enlarged, showing the rough surface of the coral, and the form of the fenestrules. 
A. 21. 1. Sticropora FENESTRATA. (Pag. 16.) 
4 a. Natural size of the branches of this coral. 
4b. A portion magnified. 
4c. A fragment of another specimen from a different locality. 
4d. Portion of the same magnified. 
4e. A part of the axis of a specimen, denuded of the outer crust, and presenting a series of concentric lines 
corresponding to the lines of progressive growth. 
Fig. 5. 22. 2. Sricropora GLOMERATA. (Pag. 17.) 
Fig. 6 a, b. 23. 1. SrreprELASMA EXPANSA. (Pag. 17.) 
Fig. 7. 24, 1. CumtetEs “. (Pag. 18.) 
7 a,b, c. The specimens considerably magnified. 7d. The ends of the tubes magnified. 
Fig. 8, 9. 25. 1. AcTINOCRINUS TENUIRADIATUS. (Pag. 18.) 
Fig. 10. 26. 2. AcTINocrINUs ———. (Pag. 18.) 
Fig. 11. 27. 1. AstTERIAs? ———. (Pag. 18.) 
11 a. Natural size. 11 b. Magnified view, 
