Observations upon Luminous Animals. 95 
The circumstance of there being points which give a 
more permanent light than the other parts of the luminous 
rings of the abdomen, has been noticed before by the Comte 
G. de Razoumouski. He states the number of these lu- 
minous points to vary from two to five *. 
T must however remark, that I never saw more than two 
of these luminous points, which were always upon the Just 
ring of the body, and that the figures w hich accompany the 
memoir of the “Comte de Razoumouski bear searcely any 
resemblance to the insect they are intended to represent $ 
from which we may fairly suspect him of inaccuracy in 
other particulars. 
As far as my observation has extended, the small sacs of 
Juminous substances are not found in any species of lam- 
pyris, except the glow-worm of this country. Thenberg 
mentions that the lampyris j japonica has two vesicles ‘on the 
tail, which afford hight. 
The organs for the peauenee of light in the genus elater 
are sitvated in the corcelet; these likewise consist of a pe- 
culiar yellow substance, placed behind transparent parts of 
the shell, which suffer the natural colour of this substance 
to be seen through them in the day, and when illuminated” 
give passage to the light. 
On dissecting the organs of light in the elater noctilucus, 
T found that there is a soft yellow substance, of an oval 
figure, lodged in the concavity of the yellow spots of the 
corcelet, which paris are particularly thin and transparent 
in this species. This substance is so remarkably close in 
ils structure, that at first yiew it appears like an Inorganic 
mass, but with alens. itis readily perceived to be composed 
of a great number of very minute parts or lobules closely 
pressed together, Around these oval masses, the intersti- 
tial substance of the corcelet is arranged in a radiated man- 
ner, and the portion of the shell that immediately covers 
the irradiated substance is in a certain degree transparent, 
but less so than that which lies over the oval masses: It is 
therefore probable, that the mterstitial substance in this 
situation may be endowed with the property of shining. 
A fasciculus of the muscles of the corcelet arises in the in- 
terior of the oval masses of the luminons substance, but 
not apparently with any design, as it contributes, with the 
adjacent fascieuli, to move the anterior feet. 
~ In the elater ignitus, the masses of Iuminous substance 
are extremely irregular in their figure: they are situated 
* Mem, de la Soc. de Lausanne, tome ii. 
| nearly 
