[ To face p. 456, vol. xix. 



On the Fossil Cokals of the West Indian Islands. Part I. 

 Appendix. By P. Martin Duncan, M.B., F.G.S. 



EKKATA, AND NOTES ON PLATES XIII.-XVI. 



Page 415, line 37, dele a, 4 b. 

 ,, 434, line 1, add 7 e. 

 ,, 442, line 30, for C. ponderosa read M.ponderosa, 



Plate XIII. 



In Figs. \ a, 2 a, and 5, the septa and the original hard parts are white, whilst, 

 from a difference in their silicification, the corresponding parts are black in 

 figs. 3, 4, and 6. 



In the natural cast, fig. 1 b, the black portions were once occupied by scleren- 

 chyma; the interstices now alone remain, being filled with a white siliceous 

 mineral. 



Fig. 8. The costag, which are often worn, are generally rather more visible than 

 those on the side nearest the number. 



10. The dark lines are the sclerenchymatous parts more or less thinned 



during mineralization, the interstices being white from infiltration. 



11. The costje are best seen at the lower margin ; the dark spots are spaces 



on either side of their extremities. In this specimen the scleren- 

 chyma is wlnte, and the interspaces black. 



12 a. The septa and wall are white in this figure, and black in fig. 12 b. 

 The natural appearance of the sclerenchyma has been nearly oblite- 

 rated by the process of silicification. 



Plate XIV. 



Fig. 9. The appearance of the costse can be determined by reference to Plate XV. 

 figs. 7 a and 7 c. 



Plate XV. 



Fig. 2 b. The columella should appear as a thin white line extending across the 

 long axis of the central black space. 



6 c. The dentations of the septa have been omitted accidentally. 



7 c. This figure represents the larger costse, the dentate smaller costae, and 



the exothecal dissepiments of Astrcsa endothecata. 



The artist has given the general appearance of the specimens, and, in most 

 instances, the minute characters also, with great exactness ; but in the others the 

 condition of the Corals and their variable colour will account for slight discre- 

 pancies.— [P. M. D.] 





