PLATE 4. 
Fig. 1. 18. 1. Retepora incepta. (Pag- 15.) 
1 a. Specimen of the natural size. 1 ft. An enlarged portion of the same. 
Fig. 2. 19. 2. Retepora gracilis. (Pag- 15.) 
2 a. Natural size of the fragment. 2 b. Enlarged portion, showing the form of the fenestrules. 
Fig. 3. 20. 1 . Gorgonia? aspera. (Pag. 16.) 
3 a. Natural size of specimen. 
3 b. Portion enlarged, showing the rough surface of the coral, and the form of the fenestrules. 
Fig. 4. 21. 1. Stictopora fenestrata. (Pag. 16.) 
4 a. Natural size of the branches of this coral. 
Ah. A portion magnified. 
4 c. A fragment of another specimen from a different locality. 
4 d. Portion of the same magnified. 
4 e. 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. 
Stictopora gloivierata. 
(Pag. 17.) 
Fig. 6 a, h 
23. 
1 . 
Streptelasma expansa. 
(Pag. 17.) 
Fig. 7. 
24. 
1 . 
CHjETETES -. 
(Pag. 18.) 
7 a, ft, c. The specimens considerably magnified. 7 d. 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 . 
Asterias? —-. 
(Pag. 18.) 
11 a. Natural 
size. 
lift. Magnified view. 
