PHOSPHORIC LIGHT. 
27 
Rose with eight tentacula (Pelagia denticulata, Pei-on), a 
third species which resembles the Medusa hysocella, an 
which VandcIIi found at the mouth ot the lagus. It ia 
known by its brownish-yellow colour, and by its tcntacu n, 
which are longer than the body. Several oi' these sea-net- 
tles were four inches in diameter : their reflection was 
almost metallic: their changeable colours of violet and pur- 
ple formed an agreeable contrast with the azure tint ol the 
C IiT'tho midst of these medusas M. Bonpland observed 
bundles of Dagysa notata, a mollusca of a singular construc- 
tion, wbicb Sir' Joseph Banks first discovered. These are 
small gelatinous hags, transparent, cylindrical, sometimes 
polygonal, thirteen lines long and two or three in diameter. 
These bags are open at both ends. In one of these open- 
digs, we observed a hyaline bladder, marked with a yellow 
spot. The cylinders lie longitudinally, one against anothei, 
like the cells of a bee-liive, and form chaplets from six to 
eight inches in length. I tried the galvanic electricity on 
.. . ... it- no contraction. It appeals 
It appears 
Cook’s first 
eigut niciies in lengui, ± 
these mollusca, but it produced no contraction, 
that the genus dagysa, formed at the time oi 
voyage, belongs to' the salpas (biphores ol Brugiuere), to 
which M. Cuvier joins the Thalia ot Brown, and the Tethys 
vagina of Tilesius. The salpas journey also by groups, join- 
ing in chaplets, as we have observed of the dagysa. 
On the morning of the 13th of June, in 34 33 labtude we 
saw large masses of this last mollusca in its passage, the se 
beino- perfectly calm. Wo observed during the night, that 
of three species of medusas which we collected none yielded 
any light but at the moment of a very slight shock. 41ns 
property does not belong exclusively to the Medusa noe- 
tiluca, which Forskafi has described in bis Fauna ^gjptuca 
and which Qmelin has applied to the Medima pelagma o 
Lcefling, notwithstanding its red tentacula, and t ic 
tuberosities of its body. If we place a very mHable medusa 
on a pewter plate, and strike against the plate \w < J 
of metal, the 1 slight vibrations of the plate are sufficient to 
make this animal emit light. Sometimes, in galian ■ £ 
medusa, the phosphorescence appears at the raomc 
the chain closes, though the exciters are not m immediate 
contact with the organs of the animal. Ihe hug 
