Observations upon Luminous Animals. 27 
The cancer fulgens bears some resemblance to the com- 
mon shrimp; it is however considerably less, the legs are 
furnished with numerous sete. The light of this animal, 
which is very brilliant,. appears to issue from every part of 
the body. hag 
The medusa pellucens measures about six inches across 
the crown or umbella; this part is marked by a number of 
opake lines, that pass off from the centre to the cirenm- 
ference. The edge of the umbella is divided into lobules, 
which succeed each other, one large and two small ones 
alternately. From within the margin of the unbella, there 
are suspended a number of long cord*shaped tentacula. 
The central part of the animal is opake, and furnished with 
four thick irregularly shaped processes, which hang down 
in the midst of the tentacula. 
This zoophyte is the most splendid of the luminous in- 
habitants of the ocean. The flashes of light emitted during 
iis contractions, are so vivid as to affect the sight of the 
spectator. i 
In the notes communicated to Sir Joseph Banks by Cap- 
tain Horsburg, he remarks that the luminous state of the 
sea between the tropics is generally accompanied with the 
appearance of a great number of marine animals of various 
kinds upon the surface of the water; to many of which he 
does not, however, attribute the property of shining. At 
other times, when the water which gave out light was ex- 
amined, it appeared only to contain small particles of a 
dusky straw colour, which dissolved with the slightest touch 
of the finger. He likewise observes, that in Bombay, cu- 
ring the hot weather of May and June, he has frequently 
seen the edges of the sea much illuminated by minute 
sparkling points. 
At sunrise on April 12, 1798, in the Arabian sea, he 
perceived several luminous spots in the water, which con- 
ceiving to be animals, be went in the boat and caught one. 
’ Jt proved to be an insect somewhat resembling in appear- 
ance the wood-louse, and was about one-third of an inch 
in length. When viewed with the microscope, it seemed 
to be formed by sections of a thin crustaceous substance. 
During the time that any fluid remained in the animal, it 
shone brilliantly like the fire-fly. 
In the monih of June in the same year, he picked up 
another luminous insect on a sandy beach, which was also 
covered with a thin shell; but it was of a different shape, 
and a larger size than the animal taken in the Arabian sea, 
By comparing the above description with an clegant es 
and- 
