424 ACALEPHA. 



met with collected in groat numbers and swimming in the same 

 direction, with their body inclined obliquely. 



The Cephe^, Per., are only distinguished from the other Rhizos- 

 toma by having filaments intermixed with the dentations of the pedi- 

 cle*. 



The Cassiope^ have no pedicle, properly so called ; their (usually 

 eiglit) arms, which are sometimes ramous, arise directly from the in- 

 ferior surface f . 



In other species, without a central mouth, we find none of those 

 numerous ramifications in the pedicle, nor open cavities for lodging 

 the ovaries. They might be united under the name of 



ASTOMA. 



Some, however — Lymnorea and Favonia, Per. — still have a large 

 pedicle furnished on each side with fibrous, filaments which may act 

 as suckers. 



Others — Geryoxia, proper. Per. — are even destitute of these fila- 

 ments, but have an infundibuliform membrane at the extremity of the 

 pedicle, from the bottom of which vessels seem to arise that ascend 

 into the pedicle and spread out through the umbella. 



One of them is found in the Mediterranean, the Med. probos- 

 cidatis, Forsk., XXXVI, 1 J. 



Orithyia, Per., 

 Where that membrane is wanting §. 



Berenix, Per.\\, 



Where there is no pedicle whatever, but where the inferior surface 

 appears to be provided Avith little suckers along the track of the ves- 

 sels^. 



pulmo, Gm., Macri, Polm. Mar. I, 13; Borlasse, XXV, 15. See Eisenh.> Ac. Nat. 

 Cur. X, part II, p. 377. 



The Potta marina, Aldrov., lb., p. 576, is perhaps another species. 



I suspect that the Ephira, Per., — Medusa simjjlex, Pennant; Borlasse, Cornw., 

 XXV, 13, 14 — is merely a Rhizostoma deprived of its pedicle. 



The Medusa pileata, Forsk., of which Peron makes an Oceania, has the ramous 

 pedicle of Rhizostoma proper, but enclosed under a campanulate umbella, furnished 

 at the margin with tentacula. 



* Medusa c.eplum, Forsk., XXIX; Encyc, XCII, 3, 4 •,—Med. octostijla, Id., XXX, 

 Encyc, lb., 4; — Med ocellata, Modeer., Nov. Act. Holm., 1791. 



t Htlcd. frondosa. Pall., Spic, X, ii, 1, 3; — Med. octopus, Gm. ; Borlasse, XXV, 

 16, 17; — Med. andromecla, Forsk., XXXI? — Med. corona, Id., p. 107? — Rhizostoma 

 leptopus, Cbamiss. aad Eisenhardt, Ac. Nat. Cur., X, p. I, pi. xxviii, f. 1 ; — Cass, 

 horbonica, Delle Chiaie, Mem., I, tab. 3, 4. 



+ Add Lianie Guhert, Zool., Freycin, pi. 84, f. 2 ; Geryonia tetraphylla, Chamiss. 

 and Eisenh., loc. cit. f. 2. 



§ Medusa minima, Raster, Op. Subs., II; — Dianee duhaul, Zool., Freycin., pi. 84, 

 f. 3, which is the Geryonle dineme. Per. It is possible that mutilated Geryoniw 

 (which are often in that condition) may have been taken for Orythyise. 



II Cuvieria carisochroma, Per., Voy. aux Terres Aust., XXX, 2. 



^ Medusa marsupialis, Gm., Plancus, Conch,, Min. Not., IV, 5 ; — Carybdea peri' 

 phyUa, Peron. 



