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Show ACALEPHA. 352 th t rojects beyond it; the • vested with a thin membrane :r ~entacula, the exterio.r ~er~ly l~s covered with a great n~~b~r with little cilia each ter~l· mfer1~r h are the longest, and fu~ms e ntain air; those in the m1d-of whtc 1 b le They somettmes co h In the centre of all ted by a go u • d most fles Y· · na h hortest simplest an f little salient proboscts. ~~:::~e~t::ula is t~e mouth, in ~heuf:~: ~yaa sort of gl~ndular sub- . le stomach sut ro It leads to a stmp . blue colour, that inhabits tance. . . k own of a beautiful One species 1S n f hot climates( 1 ). the :Mediterranean a nd seas o V ELELLA, Lam. · mout h .m tlle inferior surface in the Where, as in Porpita, there d1S da W.i th m. num erable tenta. c.u la, the edx - ~ f a proboscis, surroun e th latter are not c1hated, an a or~ o ot' which is the longest, .but e the cartilage, which is oval, te~lOr re important character 1S, ~hat nd tolerably elevated crest. still mo.t superior surface a vert~cal a 1 marked with concentric has on 1 s . d' hanous and 1S mere y This cartilage 1S tap ' . . of the same colour as str1re. A species of this gen~s also lS kn:::~s. It is eaten fried(2). the Porpt.t a. an d inhabitmg the sam f Berl Desch., n ' ·lX , 2 , 3 ·' HolothurirJ . th Med umbel/a, Mull., Natur. o xc' 6 7· Porpita gigantea, P~r., (1) It ts e . XXVI 1, i; and Encyc., ' ' • da Gm . Forsk., ' nVuo y.,, XXX· 'I , 6. . L . merely its cartilage dt. vested of the gelatine and ten· Medma porptta, ., lS The ... 5 6 if not an altered individual tacula. p 'te appendiculle, Bose., Vers, U, xvm, , ~tis the genus PoLnucax· The orp' hould constitute a separate subgenus. of the same, 8 XI k XXVI ki •••:· ~:~d~!·:;;.J~~';;,· and. th~ J!olothuri; ~i'~X~~i; !:;,: generi:.U; (2) :c 1 2 The Velella acaphtdta, Per. o~, such as the V. oblonga, . Encyc., ' , . t at there are several species, 1 xxxii different; it appears ~ dE' enh Ac. Cur. Nat., X, P· I, p • • . . tra V. lata, Chamiss. an lS ., Bt.nu ' • {'"' .. HYDROSTATICA. 383 ORDER II. HYDROST ATICA. The Hydrostatic Acalepha are known by one or more bladders usualJy filled with air, by means of which they suspend themselves in their liquid element. Excessively numerous and variously shaped appendages, some of which probably serve as suckers, and the others perhaps as ovaries, and some longer than the rest as tentacula, are attached to these vesicles and compose the whole apparent organization of these animals. They have no apparent mouth or one which can be decidedly considered as such. PHYSALIA, Lam. The Physalire resemble an extremely large oblong bladder elevated superiorly into an oblique and wrinkled crest, and furnished beneath, near one of its extremities, with numerous, cylindrical, fleshy productions, variously terminated, that communicate with the bladder. Those in the middle give origin to more or Jess numerous groups of little filaments; the lateral ones are merely divided into two threads, one of which is frequently very long. There appears to be an extremely small orifice in one of the extt·emities of the bladder, but internalJy no other intestine is found, but another bladder with thinner parietes, and creca that partly extend into the cavities of the crest. There is no nervous, circulating, nor glandular system(!). The animal swims on the surface of the sea when it is calm, employing its crest as a sail. When living, it is also furnished with extremely long filaments, moi'e slender than the others, which are sprinkled, as it were, with pearls or drops. Its touch is said to s~ing and burn like that of the Sea-nettle. They are found in all the seas of hot climates(2). (1) I have satisfied myself of this total absence of internal and complicated organs in many large individuals, so that I cannot admit the recent idea that the Physalia may be one of the Mollusca. (2} Holothuria phyaalia, L.; Ama:n., Ac., IV, iii, 6; Sloane, Jam., 1 1 iv, 5;-Me- • # |