ALCYONARIAN CORALS. 



Reduced aiudi/sis of ulci/onitrians — Continued . 



11 



9 



SiO, : 1.50 



(Al,Fe),03 i Trace. 



MgCOa 6.66 



CaCOa 84 . 50 



CaSO, 2. 15 



Ca^PsOs 1 5. 19 



10 



0.55 



.28 ' 

 13.43 

 79.84 

 5.43 1 

 .47 I 



11 



0.22 



.22 



12.52 



81.45 



1.95 



3.64 



100.00 100.00 100.00 



12 



0.04 



.24 



13.29 



79.48 



4.08 



2.87 



13 



14 



100. 00 



15 



0.45 



.15 



13.79 



85.61 



Trace. 



Trace. 



100. 00 



Analysis No. 1, that of Heliopora, might be an analysis of an ordinary coral, being nearly 

 nonmagnesian and hence different from the others. 



In two of the Gorgonias the black wiry axis was separately analyzed, although the amount 

 of material was very small. The axis of a Rhiyidogorgia sp. from Bermuda was also studied 

 and to better advantage. The three analyses are as follows: 



The axes, evidently, are composed largely of organic matter, and the inorganic portions 

 differ in composition from the more abundant calcareous envelopes. In two of them magnesia 

 is in excess of lime, and in all three the sulphates are conspicuous. To determine the exact 

 chemical nature of these axes would require much material and a longer investigation than 

 we are justified in attempting. 



A specimen of Leptogorgiaflamniea VerrLll, from the Cape of Good Hope, was also examined, 

 but it was not sufficiently perfect. Much of the cortex had been broken away, leaving an 

 excess of the axis. The partial results obtained, however, showed an exceedingly high pro- 

 portion of phosphates, and a complete study of the species is much to be desired. Indeed, 

 the genus Leptogorgia well deserves an exhaustive investigation, but perhaps more on biological 

 than on geological grounds. The fact that it contributes both magnesium carbonate and 

 calcium phosphate to the marine sediments seems to be established. 



Several other analyses of alcyonarians, partial or complete, are on record, and three of 

 them deserve reproduction here. The data are as follows: 



1. Fleurocorallium johmoni Gray. From latitude 25° 45' N.; longitude 20° 12' W., about 160 miles southwest of 

 the Canary Islands; depth of water, 2,791 meters. At that depth the temperature must have been very low, probably 

 not much above 0° C. Analysis by Anderson in Challenger Report, Deep-sea Deposits, p. 465, 1891. 



