II. GYMNOPHTHALMATA (7vnvds, naked).
1. Vessels branched (Willsiadm). Genus. Willsia, Forbes.
2. Vessels simple. Ovaries convoluted, and lining the pedunculated stomach (Oceanidce). Genera. Terris, Lesson; Saphenia, Eschscholtz ; Oceania, Peron.
3. Vessels simple, eight or more. Ovaries linear, in the course of the vessels on the sub-umbrella (,Equoreadce). Genera. Stomobrachium, Brandt ; Polyxenia, Eschscholtz.
4. Vessels simple, eight. Ovaries as many as the vessels, small, in the course of the sub-umbrella (Cireeadte). Genus. Circe, Mertens.
5. Vessels simple, four. Ovaries four, in the course of the vessels on the sub-umbrella (Geryoniadce).
Genera. Geryonia, Peron; Tima, Eschscholtz; Geryonopsis, Forbes; Thaumantias, Eschscholtz; Slabberia, Forbes.
6. Vessels simple, four. Ovaries in the substance of the peduncle (Sarriadce).
Genera. Sarsics, Lesson ; Bougainvillea, Lesson ; Lizzie, Forbes ; Mooderia, Forbes; Euphy8a, Forbes ; Steenstrupia, Forbes.
This arrangement applies to the British genera only, the species of which, with figures, are described in Professor Forbes's 'Monograph of the British Naked-Eyed Medusas; published by the Ray Society.
The second order of the Acalephie are the Cluoenana, of which De Blairsville gives the following definition :— Body gelatinous, very contractile, free, diversiform, evidently binary or bilateral, sometimes appearing subradiated, provided with a kind of straight ambulacra, formed by the approximation of two series of vibratory cilia.
Intestinal canal complete, or provided with two orifices, a mouth and a vent.
The term Ciliograde has been given to these Medusie on account of the minute organs called Vibratile Cilia, with which they are covered.
Arrangement.
De Blainville, whose amended arrangement we take, observes that systematists have hitherto agreed to imitate Gmelin more or less on the subject of the place of the Ciliograda in the animal aeries, that is to say, in making them a genus approximating to the .21fedu.sce; and he instances Lamarck, Cuvier, Latreille, and Oken, as not having expressed any doubts on the subject.
Genera.
1. Berk a. Species whose cilia are smaller than the interstices which separate them. (Genus, Berge of Esebseholtz.) Example, Berk orate, Those found by Browne seldom exceeded three inches and a half in length, or two and a half iu the largest transverse diameter. "This beautiful creature," says Browne, 'Jamaica,' p. 384, "is of an oval form, obtusely octangular, hollow, open at the larger extremity, transparent, and of a firm gelatinous consistence; it contracts and widens with great facility, but is always open and expanded when it swims or moves. The longitudinal radii are strongest at the crown or smaller extremity, where they rise from a very beautiful oblong star, and diminish gradually from thence to the margin : but each of them is furnished with a single series of short, delicate, slender appendices or limbs (the cilia) that move with great celerity either the one way or the other, as the creature pleases to direct its flexions, and in a regular accelerated succession from the top