acalephæ, or acalephæ

pl. [Gr. ἀκαληφη ( akalēphe ) = a nettle; so called from the property some of them have of imparting, when touched, a sensation like the sting of a nettle.] The third cla of the Radiata, Cuvier's fourth sub-kingdom of animals. In English they are called Sea-nettles. They were IMG:content-0066.png:[graphic][merged small] defined as zoophytes which swim in the sea, and in the organisation of which some ve els are perceived which are most frequently only productions of the intestines, hollowed in the parenchyma of the body. They were divided into Acalephæ simplices and A. hydrostat ice : the first contained the genera Medusa, Equorea, .; and the latter, Physalia, Diphyes, and others. They are now combined with the hydroid polypes to form the cla Hydrozoa. They fall under Huxley's Siphonophora, Discophora, and probably a third as yet unnamed order, to contain the animals called by Haeckel Trachymeduse. Of Acalephæ may be mentioned the genus Medusa, of which the species on our coasts are called "jelly-fish," from their jelly-like aspect; and the Physalia, or Portuguese man-of-war, which is common in more southern latitudes.