PRYSOGRADA.
Natatory organ simple and lamellar. 1. Physalia.
Generic Charactcr.—Body oval, rather elongated, more narrow and proboecidiform anteriorly, hydatiform in the middle, attenuated and obtuse posteriorly ; mouth star-shaped and terminal ; anus lateral ; a foot in form of a crest or oblique lamina, directed from before backwards; brenehite very anomalous, and comported of a great number of &vermiform cirrhosis productions ; organs of generation terminating at the anterior third of the right side by two closely approximated orifices.
Example, Physalia AreAstsa.
This is the A retAmmt of Browne ; Medusa Cararclla of Muller and Emehaeholts PAysalus Pelagieus of Lamnrek ; the Portuguese Man-of War of English voyagers. This Physalus is an inhabitant of the warm man. but a shoal of them are sometimes driven into our bays, particularly on the south-west coast.
Example, PAirophysa plarrostoma, Peron. (Macophyms Each., Aceleph.; p. 148, No. IL, t. 13, fig. 3.) 0.
Species whose tentaculiform productions are covered with cirrhiform filaments. Natatory organs unknown. (Otmus Epilmlia, Each.) Example, Rhimphysa filiferrnia. (Physsophora if/Venni*, Forak.) 2. Physeophora.
Centric Character.-13ody more or less elongated, cylindroid, hydatiform in its anterior part, provided below with two Reties of vesicular diveraiform bodies, with a regular aperture, and behind with a variable number of very diverse cirrhiform productions, two of which are longer and more complex than others ; mouth at the extremity of the hydatiform paint; anus terminal.
Example, Physsophora Mt/zest-ma.
3L de lfiainville states; that the Phymeophorm differ from the Physeim in swimming or floating in a vertical position, thenir-bag being above and the cirrhiferous productions below. The distinction of the species appears to him to depend especially on the number and form of the natatory organs.
3. Diphysa.
Centric Cliaraeler.—Body cylindrical, elongated, contractile, mus cular, composed of three parts, the anterior part vadeular, the middle part bearing on its lower part two hollow natatory organs, placed one l,efore the other, and the third part (which is the longest) provided above with a fibrillo-enpillaceous plate, and below with cirrhiform productions; mouth terminal.
Example, Diphysa singularis (Quoy and Caimard; 'Astrolabe, Zoologie ').
4. Phizophyta.
Generic Characier.—Body free, transparent, very contractile, very much elongated, swollen at one extremity into n sort of auriferous bladder with a terminal orifice, provided throughout its length with scattered tentaculiform productions mingled with cirrhiform filaments.
This genus is divided by 31 do Illainvtlle into two sections.
a.
Species with simple tentnenliform productions. Natatory organs hollow. (Germs /UsLrophysa.) . . * Species provided with two sorts of locomotivo organs, the anterior ones hollow, the posterior solid.
5. Apolemia.
Coterie Character.-13otly very much elongated, cylindrical, vermi form, provided anteriorly with many hollow natatory organs in two rows, and behind with solid 'spumous organs, between which come forth tentneuliform cirrhi, furnished with vermiform suckers.
Example, Apokmia Crania.
0. Stephanomia.
Centric Character.—Body in general very Much elongated, cylin drical, vermif5rtn, covered throughout its extent, except in the lower median line, with Nimmons natatory organs, full and dispersed in transverse bands, between which come forth, and especially inferiorly, long, very munch diversified cirrhiferm productions, mingled with the ovaries. Orifices of the intestinal canal terminal Example, Steplianomia A mph itrides, Peron ct Lesneur ('Voyago aux Torres Austr.; p. 45, pl. 29, fig. 5).
7. Protomedea.
Coterie Character.—Body free, floating, cylindrical, flattilona, very long, provided above with an imbrientod assemblage of gelatinous bodies (on two alternate rows) which are full and hippopodiform, and thraughout the rest of its length with filamentous, cirrhous, diversiform productions. Mouth .proboseidifortn, at the extremity of a sort of vesicular stomach.