Luminosity and its Origin in a South African Earthworm. 205 
to give out the luminous fluid, and, on development, the luminous patches 
appeared as shown. 
That the occurrence is not a usual one in this locality is evident from the 
fact that this particular path had been traversed almost daily, at all seasons 
of the year, and in all weathers, without any sign of the presence of such 
worms. 
These earthworms were apparently not in the normal condition, having 
probably been driven out of their burrows by the unusual wetness of the 
soil. An endeavour was therefore made to find them in their natural 
habitat, and in sufiicient quantity to afford material for more careful exam- 
ination. The spot where they were found was dug up to a considerable 
depth, but none were discovered. At other places various species of earth- 
worms were readily found, but were not luminous. On continuing the 
search, however, a species was dug up, which gave out a distinct light on 
handling, and ultimately several spots were found, where the worm could be 
got in sufficient abundance. 
How the Light is Give^i Off. 
It was not at first observed from what part of the animal the light was 
produced. In the first example procured it was found on the head and tail 
regions, as well as on other parts of the body. Subsequent and repeated 
experiments, however, seemed to indicate clearly that it was given off only 
from the mouth and anus, except in those cases when there was some injury 
to the body. The luminosity proceeded from a discharge, which was some- 
times of a viscid, mucus-like consistency, sometimes of a more fluid nature. 
This discharge was given out in various ways, but only after a certain 
amount of irritation. When first dug up the worm usually assumed a rigid 
attitude, and could be handled freely without exhibiting any movement — 
perhaps a death-feigning device. Usually, however, after a time, it began 
to exhibit very lively movements, and, by a series of strong flexures of the 
body, to throw itself about, scattering masses of luminous substance in all 
directions (Fig. 1). If held firmly to prevent such movements the fluid 
could be seen to proceed from the mouth, and, to a less extent, from the anus. 
It usually flowed out somewhat suddenly and spread over the body, but, in 
several instances, it was ejected with considerable force to some distance. 
In many instances, when examined in the dark room, spots of light appeared 
unexpectedly in various places, usually on the clothes of the observer. The 
clear pear-shaped patch in Fig. 1 is apparently produced by such an ejected 
mass of luminous fluid. 
The diversity of statement in other cases as to the region of the body on 
which the light appears may be due to the accidental contact of the body 
with the discharged mucus when the animal is captured, as was the case^ 
here. If, however, the animal is handled carefully, it may be washed in 
