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190 Mr. Silliman, Jr. on the Composition of Corals. 
on any of the species examined by him; and his investigations 
tended to show that the calcareous corals, as well as the cover- 
ings of most of the molluscs experimented upon, consisted merely 
of carbonate of lime. Such was the opinion with which these 
chemical examinations were commenced. But while they have 
found carbonate of lime to be the principal ingredient, other ele- 
ments have been detected, showing that coral is far from being the 
simple calcareous material supposed. 
The following is a list of the species examined, which are 
here numbered for the convenience of reference : 
1. Porites favosa, orn Islands. {19. Pocillopora damicornis, Sooloo. 
2. P. nigrescens, Feejee 20. P. elongata, Ce de on 
3. P. limosa, Feejees. 21. P. grandis, Fee 
4. P. cylindrica, Feeject. 22. P. ligulata, Sandwich Islands. 
5. P. fragosa, Feeje 23. P. cespitosa, Sandwich Islands. 
6. Porites,* d 24. Millepora tortuosa, Feejees 
7. Porites,* Wakes Island. 25. Heliopora cerulea, East Indies. 
‘8. Porites,* Wakes Island. 26. Gemmipora brassica, Feejee 
9. Madrepora palmata, West Indies. | 27. Dendrophyllia Sa Pisjecs. 
10. M. spicifera, Ceylon 28. Meandrina phrygia, Ce 
11. M. prolifera, Bermuda 29. Astrea orion, Ceylon 
12. M. plantaginea, Ceylon 30. Astrea, (p. 721, pl. 13, fig. 15.)t 
13. M. cytherea, Tahiti 31. Astrea, Wakes Island 
14. Madrepora, Feejees 32. Astrea, Wakes Yélaind 
15. Madrepora, Feejees 33. Astrea, Feejees 
16. Madrepora, Feejees 34. Astrea, Feejees 
17. Madrepora, Feejees. 35. Astrea, Feejees. 
18. M. cyclopea, Wakes Island. 36. Shell of Chama. 
Nine of the above species, of which there was the largest 
quantity on hand, were selected for a minute determination of 
each ingredient, while of the others, only the proportion of car- 
bonate of lime and animal matter to the other ingredients, was 
determined. 'The following are the nine selected : 
I. Porites favosa (No. 1), Sandwich Islands. 
pora palmata (No. 9), West Indies. 
It. Madrepora spicifera (No. 10), Ceylon. 
. Madrepora prolifera (No. 11), Bermudas. 
Madrepora plantaginea (No. 12), Ceylon. 
Pocillopora ligulata (No, 22), Sandwich Islands. 
. Meandrina phrygia (No. 28), Ceylon. 
VIIL. Astrea orion (No. 29), Ceylon. 
IX. Astrea (No. 30, p. 721, pl. 13, fig. 15.) 
we 
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* Worn specimens, not identified. t The references are to Mr. Dana’s work. 
i 
