Amongst the unnamed Alcyonaria in the collection of the Royal Scottish Museum, Edinburgh, is a beautiful colony belonging to the genus Cactogorgia, which Mr Eagle Clarke has kindly handed me for identification and description.

In 1907 (Trans. Roy. Soc. Edin.) I established the genus Cactogorgia for several small colonies from the Indian Ocean, and referred these to three separate species, viz. celosioides, alciformis, and expansa. Thomson and M'Kinnon, in Trans. Linn. Soc. (Zool.), 1909, have described another species from the Seychelles under the name of Cactogorgia lampas, and the present colony must also be referred to a new species. This we propose to name Cactogorgia agariciformis, n. sp., on account of its very definite mushroom-shape.