Example, Time ,flarilabrie.
Ilabitat.—The Azores. _ 'fiancee (Quoy and Gaitn.) Generic Character.—Body hemispherical, furnished on its circum ference with a small number of tentaculiform cirrhi ; excavated beneath, Lymnorer.
Generic Character.—Body subbeinispherical, furnished on its cir cumference with very fine, short, and numerous tentacular cilia ; rather deeply excavated beneath, and provided with a long proboscidi form prolongation, having at its base eight bifid and finely divided appendages. Four ovaries, in the form of a cross.
Example, Lyainoree triedre. (DianaTt triedra, Lain.) Ilahitat.—Sonth Seas.
and provided at its middle with a strong exscrted proboscidiform appendage, with four brachideous appendages at its extremity.
P,legia.
Generic Character.--Body subhemispherical, lobated, auriculatcd, furnished on its circumference with a few tentaculiform cirrhi ; eight inferior apertures at the extremity of a fistulous peduncle provided with four very strong and foliaceous arm& Four ovaries. Stomach with eseciform appendage& Pdagia!dole, Esch. (Cyenee Labiche, Quoy and Gaim.) A.
Species having a peduncle of insertion for the root, with radical appendages, besides those of the arms.
IL Species having a very short peduncle of insertion, without radical appendages, besides the four bifid arms. (Erayura, 1'r5r.) We have given an illustration of the first. The slaving grows to a very large size.
Chrysaora.
Generic Character. Body circular, hemispherical, feertooued, and provided with at least twenty-four tentruniliform cirrhi on its circum ference; excavated intenially into a considerable cavity with sacciform appendages ; communicating externally by a single orifice, piercod in the centre of a median peduncle, provided with distinct brachidoons appendages Four ovaries.
Example, Chrysaora (teem Rhezostoma.
Generic Character.—Body circular, hemispherical, provided on its circumference with lobes or festoons intermingled with auricles, largely excavated below, with four semilunar orifices, produced by four roots of insertion of a considerable pedunculated mass, afterwards divided Into eight very complex brachideoits appendages furnished with fibril lary suckers, without a median prolongation. Four ovaries, in the shape of a cross. Stomachal cavity very large and vascular at its circumference.
E x ample, Phi:al:farm.: Cori ri.
liabitat.—Buropean Seas.
M. do Blainville separates the genus into two divisions.
a, one-fourth of the disk or umbrella, seen from below ; b, disk a ithout Its appendages.
The Peltnograde :%lerlusto have been recently studied with great care by Professor E. Forbes, and ho proposes to divide them into two groups according as their eyes or ocelli are covered or destitute of this protection. When any of the more common forms of Medusa. are examined, as the species of Rhizostuma or Pdayea, it will be found that the margins of the ocelli aro protected by more or loss compli cated membranes, hoods, or lobed coverings. This character accom panies another of great importance, that is, the possession of a complicated anastomosis and nullification of the vessels. pit the case of Thasmaciias and other genera it will be found that the ocelli are either abaent or entirely nakod, and this condition is accompanied with a very simple vascular system. Hence Professor Forbes proposes the following classification.