PHORCYNIA. ACALEPHA. 413 



SECTION II. Body free. 



The greater portion of the animals of this section, forming an order in Cuvier's 

 arrangement, were included by Linnaeus in his genus Medusa. Their general fi- 

 gure is a disc, more or less convex above, similar to the head of a mushroom, with 

 the mouth below, more or less prolonged into a pedicle, and furnished with tentacu- 

 la of various forms. 



Gen. 4. PHOJICYNIA, Lam. 



Body transparent, orbicular, convex, appearing as if obtuse or 

 truncated above, concave below, with the margin broad, ob- 

 tuse, naked, and entire ; no peduncle, arms, nor tentacula. 



The genus Eulimena of Peron is included by Lamarck in the present. 



P. cudonoidea, Peron. Body thick, widest above, obtuse, rounded ; 

 stomach prominent, inversely pyramidal. Lam. ii. 494. 



Gen. 5. ^EQUOREA, Peron. Medusa, Gmel. 



Body free, orbicular, transparent, destitute of peduncle or arms, 



but furnished with tentacula ; mouth inferior and central. 



JE. rosea, Lam. Body orbicular, rose-coloured, with vascular ves- 

 sels above ; tentacula capillary, long, and numerous. Lam. ii. 497- 

 The species of this genus are very numerous in the seas of warm countries. La- 



marck includes in it the genus Foveola of Peron, distinguished by small hollows at 



the circumference. 



Gen. 6. PELAGTA, Cuv. Dianea, Lam. 

 Body orbicular, transparent, the mouth prolonged into a pedun- 

 cle, with or without arms. 



P. panopyra, Cuv. Body rose-coloured, hemispherical, centre of 



the back depressed, verrucose ; peduncle quadrifid, with eight long 



tentacula. Inhabits Atlantic Ocean Lam. ii. 509. 



In the preceding genera there are no lateral cavities ; but in the following there are, 



besides a simple mouth, four organs formed of a plicated membrane, filled at certain 



periods with an opaque substance, which Cuvier suspects to be ovaries. These are 



generally placed in open cavities on the under surface ; and the supposition of Baster 



and Muller that they were mouths, induced Peron to divide the animals into Monos- 



toma and Polyostoma. The tentacula at the circumference or mouth vary not only 



"according to the species but with age. 



Gen. 7. CYAN^A, Cuv. Medusa, Lin. 



Body orbicular, transparent, with the mouth central below, and 

 four lateral cavities ; tentacula around the circumference. 



Cuvier includes the genera Obelia and Callirhoe of Peron in this genus. 

 C. aurita, Cuv. Circumference ciliated, and acquiring with age 

 four long arms ; reddish vessels from the stomach to the circum- 

 ference. Inhabits European seas. Cuv. Reg. An. iv. 56. 



Gen. 8. RHIZOSTOMA, Cuv. 



Body orbicular, transparent, with a peduncle more or less rami- 

 fied below ; no tentacula at the circumference ; four cavities 

 on the inferior disc. 



The animals of this genus have no apparent mouth in the centre, and appear to 

 be nourished by the suction of the ramifications of their pedicle, by filaments dis- 



