IODINE IN CORALS. 403 



axial skeleton. Hundeshagen * had previously investigated 

 an iodine-containing organic substance which he separated 

 from marine sponges ; and later Hamack f isolated from the 

 same source a compound which he has termed iodospongin, 

 containing on an average 8.2 per cent of iodine. Other investi- 

 gators $ also have more recently demonstrated the presence of 

 iodine in organic combination in other marine organisms. 



Through the kindness of Professor Verrill I have had an 

 opportunity to examine specimens of three species of corals 

 which were collected in the West Indies. These species, 

 Gorgonia flabellum, Gorgonia acerosa, and Plexaura flexuosa, 

 resemble Gorgonia cavolinii in many respects. The latter 

 is, however, distinctly a Mediterranean species, while the 

 others have been found in the West Indies only. Gor- 

 gonia flabellum grows to a large size ; it is flabellate, and 

 throughout finely reticulate. The fronds are sometimes two 

 feet high and nearly as broad. The color varies from an ash 

 to a bright yellow, and is occasionally red. The polyps are 

 everywhere scattered, except where the wing-like processes 

 commence to grow from the surface, and in that case they 

 become lateral. Gorgonia acerosa is the large, purple, pendu- 

 lous species of the West Indies. When young, the branchlets 

 are erect or nearly so, and the pinnate character is less distinct 

 than in adult specimens. The latter are very large, often five 

 feet high. The axis is black. There are either one or two 

 rows of polyps on the opposite sides of the branchlets. Plex- 

 aura flexuosa has a fulvous or purplish color. The branches 

 are terete and without verrucas, but have a slightly and minutely 

 uneven surface, owing to the fact that the oscules are either 

 situated in a slight depression of the cortex, or have the inferior 

 side a little prominent. The length of the branchlets is often 

 six inches. 



* Hundeshagen, Zeitschrift fur angewandte Chemie, 1896, p. 478. 



t Harnack, Zeitschrift fur physiologische Chemie, 1898, xxiv, p. 412. 



J Eschle, Zeitschrift f iir physiologische Chemie, 1897, xxiii, p. 30. Gautier, 

 Comptes rendus de 1' Academic des Sciences, 1899, cxxviii, p. 1069. 



See Dana, Wilkes Exploring Expedition, vii, Zoophytes, pp. 660, 665, 

 668. 



