422 ACALEPHA, 
forms and very different sizes. These various degrees of complica- 
tion have given rise to numerous divisions *. 
We will designate by the general name of 
Mepwusa, 
Or Medusa proper, those which have a true mouth in the middle of 
the inferior surface, either simply open at the surface or prolonged 
into a pedicle. 
Under the name of 
AL QUOREA, 
We may re-unite those in which this mouth is simple and not pro 
longed, nor furnished with arms. 
When there are no tentacula round the umbella they constitute 
the PHoreynia of Lamarck f. 
When the circumference of the umbella is furnished with tentacu- 
la we have the AZquorEa proper—AQquoreEa of Péron—one of the 
most numerous of all the subgenera, particularly in the seas of hot 
climates f. 
Certain species are remarkable for having their inferior surface 
covered with lamine, and others—Foveroua, Péron—for little fos- 
sulze, which are placed round the circumference of the umbella §. 
We might also unite under the name of 
PeELaGiaA, 
Those in which the mouth is prolonged into a peduncle or is divided 
into arms |]. 
In all these subgenera there are no lateral cavities, but in a much 
greater number of these Medusz with a simple mouth, we find, in 
the thickness of the umbella, four organs formed of a plaited mem- 
brane, which at certain seasons are filled with an opaque substance, 
and which appear to be ovaries. They are usually placed in as 
many cavities opening on the inferior surface, or on the sides of the 
pedicle, and which have been erroneously (in my opinion) taken for 
mouths, because little animals are sometimes entangled in them 4. 
* For this genus, see the Prodromus of Péron and Lesueur, Ann. du Mus., XIV, 
and XV ; it is well to remember that their genera are frequently founded on bad 
figures, such as those of Baster and Borlasse, and without having seen the animals ; 
and that they have increased the number of species beyond all bounds. 
7 The Phorcini and Eulimenes of Péron. 
} Medusa equorea, Gn; ; Forsk., XXXI; Encyc., Vers, XCV, 1; Aquorea meso- 
nema, Péron; Forsk., XXVIII. B.;—Med. mucilaginosa, Chamiss., and Hisenh., 
Ac. Nat. Cur. X, part I. pl. xxx, f. 2, and the species engraved by M. Lesueur and 
indicated by Péron, Ann. du Mus., XV, and by M. de Lamarck, Hist., des Anim. 
sans vert., II, 498, et seq. It is to be regretted that these plates are not to be pur- 
chased. I also add to them the Pecasra, and Mexitea of Péron. 
§ Medusa mollicina, Forsk,, XXXIII, C; Encyc., XCV, 1, 2 ;—Medusa perla, the 
genus MELICERTE Péron. 
|| Pelagia panopyra, Péron, Voy. aux Terres Aust., XXXI, 2; the CALLIRHOE 
and Evacora, Pér., should also be united to it. 
{| This opinion of Baster and Miller induced Péron to divide a portion of these 
Meduse into Monostoma and Polystoma, 
