19 
M E D 
derived from their fpod, or the air they refpire, as fup- 
pofed by Carridori, the phenomenon fhould be increafed 
or diminifhed according to the quantity of food or air 
that the creatures confume. But we do not find this to 
be the cafe; for, in tliofe fituations where they are. forne- 
times found to be the moft luminous, they are deprived, 
in a great meafure, of thefe aflfumed fources of their light. 
In fait, the luminous exhibitions of living animals are 
not only independent of all foreign light, but are fre¬ 
quently deftroyed by the latter. The fhining of the me- 
dufae was always found by Mr. Macartney to ceafe upon 
She rifing of the moon, or at the approach of day ; and, 
when out of the fea, he never could excite them to throw 
out light until they had been kept for fome time in the 
dark. 
io. Medufa aurita, the four-armed eared fea-nett!e : 
convex above, with an inflefted fringed margin ; four 
arched cavities near the centre beneath, which are pro¬ 
duced into long arms. The body is hemifpherical, gela¬ 
tinous, tranfparent, with four red crefcent-fhaped fpots 
on the difk, and innumerable tentacula, or hairs, of va¬ 
rious lengths, round the margin. The under part is 
co-ncave, the centre impervious, thick, and producing 
four arms, or long jagged membranaceous folds. Thefe 
arms are entirely wanting in the younger ones ; they come 
out one by one; and at lall attain a length about twice 
the diameter of the body. 
Fig. i, on the annexed Plate, reprefents this fpecies of 
its natural fixe; by infpefting which it will be obferved, 
that, from the centre beneath to about half-way down the 
arms, there appear a kind of red purfes or folds, which 
Bafter Cuppofed to be the inteftines, or rings of the fto- 
mads; and that the finall dots or granulations with which 
thefe plica; were filled might be excrement, or perhaps 
eggs. But the microfcope has fhown thefe to be animal¬ 
cules, of various fizes and (hapes, running freely about 
in this curious network. Thefe red folds and dots, con- 
trafted with the tranfparency of the other parts, caufe a 
beautiful fplendour when the fun Ihines upon thefe ani- 
cnak. It is faid that the tentactila, and rings or plicae, 
are fometimes torn away or feparate, and fo become per¬ 
fect animals of the fame kind, in the manner of the Hydra, 
or polypus. Fig. is a fe&ion of the difk, fliowing the 
tranflucent veins, the tentacula or cirri, and the granu¬ 
lations magnified. The name, aurita, or eared, is from 
certain globules of that fhape which appear on the peri¬ 
phery of the difk, and communicate with the centre : 
thefe are perhaps the organs of nutrition and of excretion : 
one of them is fijown. upon fig. 2. and more highly mag¬ 
nified at fig. 3. Fig. 4 is a fe&ion of the rings and ten- 
tacula; and fig. 5 is a view, equally magnified, of a part 
of one of the arms, with the purfes, or folds, and animal¬ 
cules within and without. Thefe animals inhabit the 
creeks of the ocean about Norway and Stralfund, and 
likewife the Baltic Sea. If put into frefh water, they die 
within half an hour. Zocl. Dan. ii. t. 76, 77. 
si. Medufa capillata: convex above, with fixteen in¬ 
dentations round the margin, and numerous fiender fila¬ 
ments beneath. It inhabits the ocean, and is about eight 
inches in diameter. The body is delcribed as whitifh. 
Semi-pellucid, fragile ; fiat beneath, with a rough circle.; 
within -this there are eight pair of rays, and a number of 
.curled fibres and appendages from the centre; the mar¬ 
gin is divided into eight portions, each of which is emar- 
ginated. 
iz. Medufa pilearis: with a capitate difk, and eight 
{'mall holes on the border: beneath it is arched and hairy. 
The body has an irregular inflected margin. 
13. Medufa marfupialis: femi-oval, with four tentacula 
4)n the margin, and refembles a purfe. Inhabits the Me¬ 
diterranean. 
14. Medufa pelagica: hemifphericai- concave, with a 
erenate curved margin and eight tentacula. Found in the 
.American and Atlantic feas. 
.jj, Medufa no&iluca; deprefifed, with reddifh-browra 
U S A. 
warts and dots; margin with eight red tentacula, -It is 
defcribed by Forfkal as meafuring about three inches in 
diameter, and about one and a half inch in depth ; fur- 
face convex, of a reddifn glafs colour, with brown fpots ; 
margin notched into fixteen lobules. The central part, 
containing the vifcera, hangs down for fome way, and is 
furrounded by eight foinewhat-broad tentacula. This 
fpecies is reported to be extremely luminous, particularly 
.round the margin. 
16. Medufa fulca : body with fixteen brown rays and 
a brown circle in the middle ; the circumference edged 
with alternate crooked fangs and oval tubercles. It inha¬ 
bits the coaft of Cornwall. 
17. Medufa purpura: body decorated with pale purple 
rays, and a light purple crofs in the centre, between each 
bar of which is a deep purple horfe-fhoe-fhaped mark. 
18. Medufa tuberculata: fifteen brown rays meeting 
at the centre, and fmall oval tubercles round the margin; 
it has four tentacula, plain, and much longer than the 
body. 
19. Medufa undulata: margin undulate, with fangs on 
the projecting parts; beneath, four orifices, between which 
is a ftem divided into eight ragged tentacula. 
20. Medufa lunulata: margin tuberculate ; beneath in 
the centre are four conic appendages forming a crofs, 
with feveral others, like ferrate leaves, ftirrounding it. 
The tentacula are eight, not longer than the margin, and 
between each is a femilunar aperture. Inhabits the coaft 
of Cornwall, with the two preceding. 
21. Medufa nuda: orbicular, blue, without creft; the 
tentacula of the difk are naked, filiform,- with three rows 
of glands. It is found in the Mediterranean, and is never 
an inch in diameter. The body has a whitifh difk above, 
and radiate with concentric Arias, the margin and border 
blue. 
22. Medufa velelia : orbicular, blue, with an oblique 
fimple creft or membrane, and numerous tentacula be¬ 
neath. Inhabits the Atlantic and Mediterranean feas. 
43. Medufa fpirans: oval, blue, with oblique divided 
crelt or veil, and numerous filiform tentacula beneath. It 
is about two inches long, and inhabits the Mediterranean. 
Body thin, convex, and terminating in a whitifh central 
knob above, blue, with a brown border; creft two-parted 
and ftriate. 
44. Medufa pulmo, the eight-armed fea-nettle: hemi- 
fpherical-concave, with a fringed border ; beneath ftriate ; 
the ftem with four openings and eight arms. It inhabits 
the Tufcan fea. Body gelatinous, pellucid, tough, crys¬ 
talline. The head is large, hemifpherical, concave be¬ 
neath, and marked with numerous ftriae, crofied by fix¬ 
teen diftant ligaments, each emitting a fhort branch on 
both fides; border fringed with numerous roundifh fcal- 
lops. Stem large, thick, fquare, with four femi-oval open¬ 
ings, each of which has a final! lobe above, and a fmaller 
beneath. Eight branches, or arms, proceeding from the 
lower part of the ftem, fub.cylindric, pendent, and wrinkled 
behind; befides thefe, there are fixteen fubtrigonal ap¬ 
pendages rifing from the beginnings of the branches, bifid 
in front, and terminated on the upper fide by a fiat wrinkled 
Surface; the branches end in as many f ub-pyramidical 
branchiae, the two exterior fides of which are prominent, 
and ending in a thickly-wrinkled furface; thefe are ter¬ 
minated by eight oblong fub-trianguiar thick pendent 
bodies, ending in three flat acute membranaceous pieces. 
Within the openings is a flexuous ftriate bluifh-yellov/ 
band. This is reprefented at fig. 6. from Shaw’s Nat. Mifcel. 
25. Medufa tyrrhena: convex, the margin erenate, 
and furniflied with very long fibres or threads; beneath 
are four tentacula. The body is finooth, tender, hyaline, 
Spotted with red ; beneath are four cavities, each marked 
with a red band. This, as its name imports, is found in 
the Tufcan fea. 
a6. Medufa tubercularis : difk prominent; margin eight 
times divided, and ftriate beneath ; it has eight tubercles. 
The body is hyaline, and it is often two pounds weight; 
4 beneath 
